Fermentation doi: 10.3390/fermentation10040185
Authors: Yamin Zhang Haiyang Yan Xiangxiu Xu Xiaowei Xiao Yuan Yuan Na Guo Tiehua Zhang Mengyao Li Ling Zhu Changhui Zhao Zuozhao Wang Haiqing Ye
Dongbei Suaicai (DBSC) has a complicated microbial ecosystem in which the composition and metabolism of microbial communities during the process have not been well explored. Here, combined metagenomic and metaproteomic technology was used to reveal the taxonomic and metabolic profiles of DBSC. The results showed that firmicutes and proteobacteria were the prevalent bacteria in phylum and Pseudomonas, while Weissella, Pediococcus, and Leuconostoc were the prevalent genus. The vital metabolic pathways were involved in glycolysis/gluconeogenesis [path: ko00010], as well as pyruvate metabolism [path: ko00620], fructose and mannose metabolism [path: Ko00051], glycine, and serine and threonine metabolism [path: Ko00260]. Moreover, the key proteins (dps, fliC, tsf, fusA, atpD, metQ, pgi, tpiA, eno, alaS, bglA, tktA, gor, pdhD, aceE, and gnd) in related metabolized pathways were enriched during fermentation. This study will aid in facilitating the understanding of the fermentation mechanisms of DBSC.
]]>Fermentation doi: 10.3390/fermentation10040184
Authors: Zhuoyu Wang Andrej Svyantek Zachariah Miller Aude A. Watrelot
Blackcurrant is well known for its health benefits, but its wine products are understudied. In this research, studies were conducted after non-Saccharomyces and Saccharomyces yeast strain inoculation in less than 20% (w/v) fruit must for blackcurrant fermentation. Three inoculations were carried out on blackcurrant musts, as follows: (1) sequential inoculation with Torulaspora delbrueckii (strain Biodiva) followed by Saccharomyces EC1118 strain; (2) sequential inoculation with Metschnikowia pulcherimma (strain Flavia) followed by EC1118; (3) single-strain inoculation with EC1118 as the control treatment. None of these treatments did alter sugar consumption dynamics. Biodiva inoculation had impacts on both color dynamic parameter changes and final wine color profiles compared to EC1118. The final wine compositions indicate that Biodiva treatment had a significant impact on wine pH and acidity, whereas EC1118 single-strain largely influenced wine ethanol and glycerol contents. Although the total antioxidant capabilities were close among the three produced wines, the monophenol profiles indicate that Biodiva enhanced the total anthocyanin and hydroxycinnamates content but reduced the total flavanol contents in the final wine. EC1118 and Flavia wines contained more total flavanols compared to Biodiva treatment. The nonflavonoid profiles indicate that there were no significant differences among the three treatments. Our findings provide useful information for the application of yeast strains in blackcurrant wine fermentation.
]]>Fermentation doi: 10.3390/fermentation10040183
Authors: Chiara Nasuti Lisa Solieri
Yeast is a powerful bioflavoring platform, suitable to confer special character and complexity to beer aroma. Enhancing yeast bioflavoring represents a chance for the brewing production chain to diversify its product portfolio and to increase environmental sustainability in the era of climate change. In flavor compound metabolism, multiple genes encoding biosynthetic enzymes and the related regulatory factors are still poorly known, but significant advances have been recently made to dissect gene contribution in flavor molecule production. Furthermore, causative mutations responsible for the huge strain diversity in yeast bioflavoring aptitude have been recently disclosed. This review covers the most recent advances in the genetics of yeast bioflavoring, with special regards to higher alcohols, esters, monoterpene alcohols, thiols, and phenolic derivatives of hydroxycinnamic acids. We also critically discussed the most significant strategies to enhance yeast bioflavoring, including bioprospecting for novel Saccharomyces and non-Saccharomyces strains, whole-genome engineering, and metabolic engineering.
]]>Fermentation doi: 10.3390/fermentation10040182
Authors: Hongliang Mu Peifang Weng Zufang Wu
In the original publication [...]
]]>Fermentation doi: 10.3390/fermentation10040181
Authors: Nazir Ahmad Khan Mussayyab Khan Abubakar Sufyan Ashmal Saeed Lin Sun Siran Wang Mudasir Nazar Zhiliang Tan Yong Liu Shaoxun Tang
Sugarcane (Saccharum officinarum) bagasse (SCB) is one of the most widely produced lignocellulosic biomasses and has great potential to be recycled for sustainable food production as ruminant animal feed. However, due to severe lignification, i.e., lignin-(hemi)-cellulose complexes, ruminants can only ferment a minor fraction of the polysaccharides trapped in such recalcitrant lignocellulosic biomasses. This study was therefore designed to systematically evaluate the improvement in nutritional value, the in vitro dry matter digestibility (IVDMD), and the rate and extent of in vitro total gas (IVGP) and methane (CH4) production during the 72 h in vitro ruminal fermentation of SCB, bioprocessed with Agaricus bisporus, Pleurotus djamor, Calocybe indica and Pleurotus ostreatus under solid-state fermentation (SSF) for 0, 21 and 56 days. The contents of neutral detergent fiber, lignin, hemicellulose and CH4 production (% of IVGP) decreased (p < 0.05), whereas crude protein (CP), IVDMD and total IVGP increased (p < 0.05) after the treatment of SCB for 21 and 56 days with all white-rot fungi (WRF) species. The greatest (p < 0.05) improvement in CP (104.1%), IVDMD (38.8%) and IVGP (49.24%) and the greatest (p < 0.05) reduction in lignin (49.3%) and CH4 (23.2%) fractions in total IVGP were recorded for SCB treated with C. indica for 56 days. Notably, C. indica degraded more than (p < 0.05) lignin and caused greater (p < 0.05) improvement in IVDMD than those recorded for other WRF species after 56 days. The increase in IVGP was strongly associated with lignin degradation (R2 = 0.72) and a decrease in the lignin-to-cellulose ratio (R2 = 0.95) during the bioprocessing of SCB. Our results demonstrated that treatment of SCB with (selective) lignin-degrading WRF can improve the nutritional value and digestibility of SCB, and C. indica presents excellent prospects for the rapid, selective and more extensive degradation of lignin and, as such, for the improvement in nutritional value and digestibility of SCB for ruminant nutrition.
]]>Fermentation doi: 10.3390/fermentation10040180
Authors: Xiaofen Fu Liyun Guo Yumeng Li Xinyu Chen Yumei Song Shizhong Li
Increasingly high interest in yeast–yeast interactions in mixed-culture fermentation is seen along with beer consumers’ demands driving both market growth and requests for biotechnological solutions that can provide better sensory characteristics. In this study, Lachancea thermotolerans and Saccharomyces cerevisiae with a cell population ratio of 10:1 were inoculated for sour beer fermentation while the process conditions within the brewing industry remained unchanged. With L. thermotolerans producing lactic acid (1.5–1.8 g/L) and bringing down the pH to 3.3–3.4 whilst adding no foreign flavors herein, this study revealed a new natural, fruity sour beer with a soft, sour taste. In this study, the double-yeast mixed-culture fermentation produced more flavor substances than a single-culture process, and plenty of isobutyl acetate and isoamyl acetate enhanced the fruit aroma and balanced the sour beer with a refreshing taste. While playing a positive role in improving the beer’s quality, the double-yeast mixed-culture fermentation developed in this study helps to offer an alternative mass production solution for producing sour beer with the processes better controlled and the fermentation time reduced. The stress responses of the L. thermotolerans during the fermentation were revealed by integrating RNA sequencing (RNA-Seq) and metabolite data. Given that the metabolic flux distribution of the S. cerevisiae during the fermentation differed from that of the non-Saccharomyces yeasts, transcriptional analysis of non-Saccharomyces yeast and S. cerevisiae could be suitable in helping to develop strategies to modulate the transcriptional responses of specific genes that are associated with the aroma compounds released by S. cerevisiae and non-Saccharomyces yeasts. In the case of some non-Saccharomyces yeast species/strains, the diversion of alcoholic fermentation and the formation of a great number of secondary compounds may, in part, account for the low ethanol yield.
]]>Fermentation doi: 10.3390/fermentation10040179
Authors: Yan Zhou Xuedong Zhang Yue Wang Hongbo Liu
Amino acids, particularly the ones that cannot be synthesised during fermentation, are reportedly to be key nutrients for anaerobic fermentation processes, and some of the acids are also intermediate products of anaerobic fermentation of protein-rich waste. To date, particularly, there is a lack of research on the effects of some amino acids, such as cysteine, glycine, aspartic acid, and valine, on lactic production from the fermentation of food waste and also the mechanisms involved in the process. Thus, this study investigated the effects of the four different amino acids on lactic acid production during the acidic anaerobic fermentation of food waste. Firstly, batch experiments on synthetic food waste at different pHs (4.0, 5.0, and 6.0) were executed. The results harvested in this study showed that higher LA concentrations and yields could be obtained at pH 5.0 and pH 6.0, compared with those at pH 4.0. The yield of lactic acid was slightly lower at pH 5.0 than at pH 6.0. Furthermore, caustic consumption at pH 5.0 was much lower. Therefore, we conducted batch experiments with additions of different amino acids (cysteine, glycine, aspartic acid, and valine) under pH 5.0. The additions of the four different amino acids showed different or even opposite influences on LA production. Glycine and aspartic acids presented no noticeable effects on lactic acid production, but cysteine evidently enhanced the lactic acid yield of food waste by 13%. Cysteine addition increased α-glucosidase activity and hydrolysis rate and simultaneously enhanced the abundance of Lactobacillus at the acidification stage as well as lactate dehydrogenase, which also all favoured lactic acid production. However, the addition of valine evidently reduced lactic acid yield by 18%, and the results implied that valine seemingly inhibited the conversion of carbohydrate. In addition, the low abundance of Lactobacillus was observed in the tests with valine, which appeared to be detrimental to lactic acid production. Overall, this study provides a novel insight into the regulation of lactic acid production from anaerobic fermentation of food waste by adding amino acids under acidic fermentation conditions.
]]>Fermentation doi: 10.3390/fermentation10040178
Authors: D. Daniela Maza Julio Maximiliano Barros José Manuel Guillamón Manuel J. Aybar Silvana C. Viñarta
Single-cell oils (SCOs) offer a promising alternative to conventional biodiesel feedstocks. The main objective of this work was to obtain SCOs suitable for biodiesel production from the oleaginous yeast Rhodotorula glutinis R4 using sugarcane vinasse from a local sugar-derived alcohol industry as the substrate. Additionally, crude glycerol from the local biodiesel industry was evaluated as a low-cost carbon source to replace expensive glucose and as a strategy for integrating the bioethanol and biodiesel industries for the valorization of both agro-industrial wastes. R4 achieved a high lipid accumulation of 88% and 60% (w/w) in vinasse-based culture media, containing 10% and 25% vinasse with glucose (40 g L−1), respectively. When glucose was replaced with crude glycerol, R4 showed remarkable lipid accumulation (40%) and growth (12.58 g L−1). The fatty acids profile of SCOs showed a prevalence of oleic acid (C18:1), making them suitable for biodiesel synthesis. Biodiesel derived from R4 oils exhibits favorable characteristics, including a high cetane number (CN = 55) and high oxidative stability (OS = 13 h), meeting international biodiesel standards (ASTMD6751 and EN14214) and ensuring its compatibility with diesel engines. R. glutinis R4 produces SCOs from vinasse and crude glycerol, contributing to the circular economy for sustainable biodiesel production.
]]>Fermentation doi: 10.3390/fermentation10040177
Authors: Isabela Maria Macedo Simon Sola Larissa Deckij Evers José Pedro Wojeicchowski Tatiane Martins de Assis Marina Tolentino Marinho Ivo Mottin Demiate Aline Alberti Alessandro Nogueira
Pure, co-, and sequential fermentations of Hanseniaspora uvarum, H. guilliermondii, and Saccharomyces cerevisiae strains were evaluated to improve the aromatic quality of ciders. In sequential fermentations, Hanseniaspora strains were used as starter, followed by S. cerevisiae inoculation succeeding one, two, and three days of fermentation. Kinetics, physicochemical parameters, and volatile compounds were assessed during 10 days of fermentation. The headspace technique was used to capture the volatile compounds from the ciders obtained in each experiment and analyzed by gas chromatography. Fermentations with pure strains of Hansenisaspora sp. showed a high population (>1010 CFU/mL) but had a low fermentation rate (2.3–3.8 CO2 g/L/d), low consumption of amino acids (20–40 mg/L) with a high residual content, high sugar consumption (80–90 g/L), and low alcohol content (<2.0% v/v). The H. uvarum strain produced a notably high ester content (245 mg/L). In the co-fermentations, H. guilliermondii with S. cerevisiae highlighted a significant production of higher alcohols, similar to that produced by S. cerevisiae alone (152–165 mg/L). In general, the maximum fermentation rate of the sequential inoculations was lower than co-fermentations but showed low residual nitrogen content (<69 mg/L) and good conversion of sugars into ethanol (4.3–5.7% v/v). The highest concentrations of volatile compounds were observed in treatments involving the two non-conventional strains: H. uvarum with S. cerevisiae inoculation after three days (564 mg/L) and H. guilliermondii after just one day (531 mg/L) of fermentation. These differences stemmed from the metabolic activity of the strains. H. uvarum was influenced by the presence of Saccharomyces, whereas H. guilliermondii did not exhibit this effect. Thus, a pure H. uvarum inoculum has the potential to produce a demi-sec cider with low alcohol content and high content of esters, contributing to a fruity aroma. In addition, ciders with sequential inoculation were the most promising for dry cider processing concerning fermentation parameters and bioaroma enrichment.
]]>Fermentation doi: 10.3390/fermentation10040176
Authors: Jingyao Huang Sujing Yang Huali Jian
In this study, the wild-type Rhodotorula mucilaginosa GDMCC 2.30 and its high carotenoid-producing mutant JH-R23, which was screened from the space mutation breeding treated wild type, were used as materials. Through whole-genome sequencing and resequencing analysis, the carotenoid metabolic pathway and mechanism of high carotenoid production in the mutant were explored. The R. mucilaginosa GDMCC 2.30 genome comprised 18 scaffolds and one circular mitochondrial genome with a total size of 20.31 Mb, a GC content of 60.52%, and encoding 7128 genes. The mitochondrial genome comprised 40,152 bp with a GC content of 40.59%. Based on functional annotations in the GO, KEGG, and other protein databases, nine candidate genes associated with carotenoid metabolic pathways, and candidate genes of the CrtS and CrtR homologous gene families were identified. The carotenoid metabolic pathway was inferred to start from sugar metabolism to the mevalonate pathway, as is common to most fungi, and the final product of the mevalonate pathway, geranylgeranyl diphosphate, is a precursor for various carotenoids, including β-carotene, lycopene, astaxanthin, and torularhodin, formed through the activity of crucial enzymes encoded by genes such as CrtI, CrtYB, CrtS, and CrtR. Resequencing analysis of the mutant JH-R23 detected mutations in the exons of four genes, including those encoding Gal83, 3-oxoacyl-reductase, p24 proteins, and GTPase. These mutations are interpreted to have an important impact on carotenoid synthesis by JH-R23.
]]>Fermentation doi: 10.3390/fermentation10040175
Authors: Tong Liu Qingqing Cao Fan Yang Jianjun Lu Xianglian Zeng Jianghua Li Guocheng Du Huabin Tu Yanfeng Liu
Methanol, also known as wood alcohol, is a common hazardous by-product of alcoholic beverage fermentation and serves as a crucial indicator for assessing the safety of alcoholic beverages. However, the metabolic mechanisms of methanol production during the solid-state fermentation of Chinese Baijiu remain unclear. In this study, we sought to determine the primary stage of methanol production in Chinese Baijiu by measuring the methanol content at different stages of fermentation. High-throughput multi-omics sequencing techniques were employed to elucidate methanol metabolic pathways and associated microorganisms. In addition, a comprehensive analysis incorporating environmental factors and microbial interactions was conducted to explore their combined effects on methanol production. Methanol was predominantly produced during pit fermentation, with the most significant increase observed within the first seven days. Microorganisms such as Pichia kudriavzevii, Byssochlamys spectabilis, Penicillium, and Aspergillus played a regulatory role in methanol content during the first seven days through their involvement in butyrate and methane metabolic pathways and pectin degradation modules. During Baijiu production, various types of molds and yeasts participate in methanol production. Differences in their abundance within fermentation cycles may contribute to variations in methanol content between stages. Lactobacillus accumulated abundantly in the first seven days in each stage, suppressing methanol-metabolizing microorganisms. In addition, the increased acidity resulting from Lactobacillus metabolism may indirectly promote methanol generation.
]]>Fermentation doi: 10.3390/fermentation10030174
Authors: Tomislava Grgić Saša Drakula Bojana Voučko Nikolina Čukelj Mustač Dubravka Novotni
Dough retardation is commonly used to extend dough shelf-life, but it poses a challenge for flatbreads due to their large surface. This study explored the sourdough fermentation of oats and barley, addressing challenges in the retardation of dough for flatbread. Sourdough, using flour only or flour blended with bran (3:1), was fermented with a LIVENDO LV1 starter at 30 °C for 24 h. The pH value, microbial viable cell count, total titratable acidity and organic acids concentration of the sourdough were measured. The properties of dough and flatbread, depending on the retardation time (24 h and 48 h), sourdough type (oat or barley) and sourdough level (30% or 50% dough weight), were investigated. Oat flour’s limited acidification improved with the inclusion of bran, resulting in a desirable pH, TTA, and lactic to acetic acid ratio after 15 h of fermentation, which were comparable to results achieved with barley sourdough. The sourdough addition slowed down the enzymatic browning of dough during retardation. Dough retardation at 24 h reduced the phytates content (32–38%) and crumb hardness (9–16%), depending on the sourdough type and level. In dough retardation, β-glucans were degraded by up to 9% in the case of oats and by up to 28% in the samples with barley. Overall, adding oat or barley sourdough at a 30% dough weight can be recommended to enhance flatbread’s nutritional value and prolong its shelf life.
]]>Fermentation doi: 10.3390/fermentation10030173
Authors: Meijia Zhao Shaoheng Bao Jiajia Liu Fuli Wang Ge Yao Penggang Han Xiukun Wan Chang Chen Hui Jiang Xinghua Zhang Wenchao Zhu
Tricyclene, a tricyclic monoterpene naturally occurring in plant essential oils, holds potential for the development of medicinal and fuel applications. In this study, we successfully synthesized tricyclene in E. coli by introducing the heterologous mevalonate (MVA) pathway along with Abies grandis geranyl diphosphate synthase (GPPS) and Nicotiana sylvestris tricyclene synthase (TS) XP_009791411. Initially, the shake-flask fermentation at 30 ◦C yielded a tricyclene titer of 0.060 mg/L. By increasing the copy number of the TS-coding gene, we achieved a titer of 0.103 mg/L. To further enhance tricyclene production, optimal truncation in the N-terminal region of TS XP_009791411 resulted in an impressive highest titer of 47.671 mg/L, approximately a 794.5-fold improvement compared to its wild-type counterpart. To the best of our knowledge, this is the highest titer of the heterologous synthesis of tricyclene in E. coli. The SDS-PAGE analysis revealed that lowering induction temperature and truncating the random coil N-terminal region effectively improved TS solubility, which was closely associated with tricyclene production levels. Furthermore, by truncating other TSs, the titers of tricyclene were improved to different degrees.
]]>Fermentation doi: 10.3390/fermentation10030172
Authors: Ronnie G. Willaert
This Special Issue continues the “Yeast Biotechnology” Special Issue series of the MDPI journal Fermentation [...]
]]>Fermentation doi: 10.3390/fermentation10030171
Authors: Thomas Bintsis Photis Papademas
In the original publication [...]
]]>Fermentation doi: 10.3390/fermentation10030170
Authors: Xinyu Zhang Zhijun Cao Hongjian Yang Yajing Wang Wei Wang Shengli Li
Rumen metabolism is closely related to feed utilization and the environmental adaptability of cows. However, information on the influence of altitude on ruminal metabolism is limited. Our study aimed to investigate differences in rumen metabolism and blood biochemical indicators among Sanhe heifers residing at various altitudes. A total of 20 serum and ruminal fluid samples were collected from Sanhe heifers in China, including those from Hulunbeier City (approximately 700 m altitude; 119°57′ E, 47°17′ N; named LA) and Lhasa City (approximately 3650 m altitude; 91°06′ E, 29°36′ N; named HA). Compared with LA heifers, HA heifers had higher levels of serum cortisol, glucose, and blood urea nitrogen (p < 0.05) and lower Ca2+ concentrations (p < 0.05). Using liquid chromatography–mass spectrometry (LC–MS)-based untargeted metabolomic technology, we identified a significant difference in 312 metabolites between the LA and HA groups. Metabolic pathway analysis, based on significantly different rumen metabolites, identified 20 enriched metabolic pathways within hierarchy III, which are encompassed within 6 broader metabolic pathways in hierarchy I. This study constitutes the first elucidation of the altitudinal adaptation mechanism of ruminants from the perspective of rumen metabolism, thereby offering a novel angle for investigating high-altitude adaptation in both humans and animals.
]]>Fermentation doi: 10.3390/fermentation10030169
Authors: Sarah Silva Angélica Olivier Bernardi Marcelo Valle Garcia Thais Nunes Bisello Larissa Borstmann Marina Venturini Copetti
Contamination caused by fungi stands out as a significant microbiological issue in the food industry, particularly leading to premature spoilage across various food segments, including the dry-fermented meat industry. The emergence of undesired fungi on product surfaces results in substantial economic losses. Once microorganisms infiltrate the food, contamination ensues, and their subsequent proliferation can adversely impact the product’s appearance, odor, flavor, and texture. This, in turn, leads to consumer rejection and negatively affects the commercial brand. Additionally, concerns persist regarding the potential presence of mycotoxins in these products. Given the detrimental effects of spoilage fungi in the food industry, practices such as thorough cleaning and sanitization become crucial to prevent contamination and subsequent premature deterioration. These measures play a pivotal role in ensuring the quality and safety of food, while also extending the shelf life of products. This review delves into the advantages, disadvantages, and factors that may influence the efficacy of commonly used sanitizers in the dry-fermented cured meat industry, including substances like sodium hypochlorite, peracetic acid, and benzalkonium chloride.
]]>Fermentation doi: 10.3390/fermentation10030168
Authors: Yulma Lizbeth Aguirre-Garcia Sendar Daniel Nery-Flores Lizeth Guadalupe Campos-Muzquiz Adriana Carolina Flores-Gallegos Lissethe Palomo-Ligas Juan Alberto Ascacio-Valdés Leonardo Sepúlveda-Torres Raúl Rodríguez-Herrera
Studies on fermentation by acid lactic bacteria (LAB) have confirmed the presence of strains with attributes of considerable relevance for food processing. These strains, in addition to their ability to modify the texture and flavor of foods, possess beneficial properties for human health. They enhance food quality by making it more nutrient-rich and contribute to food preservation. The production of lactic acid, vitamins, exopolysaccharides, and bacteriocins, among other compounds, confers these properties to LAB. In the realm of preservation, bacteriocins play a crucial role. This is because bacteriocins act by inhibiting the growth and reproduction of unwanted microorganisms by interacting with the cell membrane, causing its rupture. This preservative effect has led LAB to have widespread use during food processing. This preservative effect has led to widespread use of LAB during food processing. This review highlights the importance of fermentation carried out by LAB in the food industry and in the bio-preservation of foods. These findings emphasize the relevance of continuing investigations and harness the properties of LAB in food production.
]]>Fermentation doi: 10.3390/fermentation10030167
Authors: Lihong Wang Ganghua Li Xueqin Tian Yitong Shang Huanhuan Yan Lihua Yao Zhihong Hu
Cordyceps militaris (C. militaris) is a valued medicinal fungus that can be traced back thousands of years in traditional Chinese medicine (TCM). Both TCM and modern scientific research have confirmed the positive effects of C. militaris on human health. In recent years, C. militaris has gained wide popularity; unfortunately, strains often degrade during cultivation, resulting in a decline in fruiting bodies and active components that negatively impacts the development of C. militaris in the health food and medicine industries. This review summarizes the current progresses in research on the genomic, transcriptomic, proteomic, and genetic manipulation of C. militaris and discusses its primary metabolites and strain degradation mechanisms. The current challenges and future prospects of C. militaris research are also discussed.
]]>Fermentation doi: 10.3390/fermentation10030166
Authors: Burcu Şirin Kaya Emrah Nikerel
Despite being frequently encountered, the effect of oxidative or reductive stress on the intracellular metabolism and the response of the intracellular metabolome of yeasts is severely understudied. Non-conventional yeasts are attracting increasing attention due to their large substrate portfolio of non-canonical pathways as well as their production and secretion of proteins. To understand the effects of both stresses on yeast, the conventional model yeast S. cerevisiae and the non-conventional model yeast P. pastoris were perturbed with 5 mM of hydrogen peroxide for oxidative stress and 20 mM of dithiothreitol for reductive stress in well-defined chemostat cultures at a steady state, and fermentation profiles, intracellular amino acid levels, and intracellular glutathione levels were measured. Although stable profiles of extracellular metabolites were observed, significant changes were measured in intracellular amino acid levels within the first five minutes. Collectively, the amino acids ranged from 0.5 to 400 µmol/gDW, with the most significant increase upon the induction of oxidative stress being seen in cysteine (up to 90%) for S. cerevisiae and in aspartate (up to 80%) for P. pastoris. Upon the induction of reductive stress, asparagine nearly halves in S. cerevisiae, while tryptophan decreases by 60% in P. pastoris. By inspecting the time traces of each amino acid, possible mechanisms of pathway kinetics are speculated. This work furthers our understanding of the response of metabolism to oxidative stress in two model yeasts.
]]>Fermentation doi: 10.3390/fermentation10030165
Authors: Jake A. K. Elliott Christian Krohn Andrew S. Ball
Anaerobic digestion is a potential treatment for industrial wastewater that provides valuable end-products, including renewable energy (biogas). However, waste streams may be too variable, too dilute at high volumes, or missing key components for stable digestion; all factors that increase costs and operational difficulty, making optimisation crucial. Anaerobic digestion may benefit from process intensification, particularly the novel combination of high-strength source-separated wastewater to minimise volume, together with the use of biosolids biochar as a chemical and microbial stabiliser. This study investigates the stability, yield, and microbial community dynamics of the anaerobic digestion of source-separated industrial wastewater from a food manufacturer and a logistics company, using biosolids biochar as an additive, focusing on gas and volatile fatty acid (VFA) production, process stability, and the microbial community using bench-scale semi-continuous reactors at 30- and 45-day hydraulic retention time (HRT). While gas yields were lower than expected, stability was possible at high HRT. Methane production reached 0.24 and 0.43 L day−1 per litre reactor working volume at 30- and 45-day HRT, respectively, despite high VFA concentration, and was linked to the relative abundance of Methanosarcina in the microbial community. Interactions between substrate, VFA concentration, and the microbial community were observed. Biochar-assisted anaerobic digestion holds promise for the treatment of source-separated wastewater.
]]>Fermentation doi: 10.3390/fermentation10030164
Authors: Victoria Lizama Inmaculada Álvarez María José García-Esparza
The application of the ultrasound technique (US) in the production of rosé and red wines has demonstrated that the aromatic composition of rose wine can be affected and that it contributes to increasing the color of red wines without increasing the extraction of astringent tannins. The ultrasound treatment has favored the extraction of anthocyanins, which has had an impact on the increase in color density (C.D.) and has allowed greater color stability over time. Moreover, significant differences have been found between the two US systems applied, with continuous treatment being more effective in the extraction of phenolic compounds than pulsed treatment. The application system of the US also affects the aromatic composition of the wines. These results are of interest, as some esters have been described as important odorants in wines.
]]>Fermentation doi: 10.3390/fermentation10030163
Authors: Isadora Cogo Badan Sun-Hwa Jung Rickwinder Singh Vivekanand Vivekanand Justus Knappert Cornelia Rauh Christoph Lindenberger
In the pursuit of sustainable solutions for contemporary environmental challenges arising from the increasing global demand for energy, this study delves into the potential of cyanobacteria, specifically Arthrospira platensis (commonly known as “spirulina”), as a versatile resource. Employing a life cycle assessment (LCA) in accordance with the ISO 14044:2006 standard and employing both midpoint and endpoint indicators, the study comprehensively evaluates environmental impacts. The research explored a range of scenarios, specifically investigating variations in light intensity and harvesting volume. These investigations were carried out using a pilot-scale photobioreactor, specifically an airlift reactor system featuring a horizontal tubular downcomer. The primary focus is on extracting valuable compounds, namely exopolysaccharides and phycocyanin. It emphasized the extraction of value-added products and strategic integration with a biogas plant for process heat, contributing to developing a sustainable supply network and offering insights into environmentally conscious algae cultivation practices with implications for renewable energy and the production of valuable products. The results emphasize the project’s potential economic feasibility with minimal energy impact from by-product extraction. The environmental assessment identifies marine ecotoxicity and fossil resource depletion as principal impacts, predominantly influenced by upstreaming and harvesting stages. After conducting comparisons across various scenarios, it was found that cultivations under higher light intensities have a lower environmental impact than cultivations with low light supply. However, regardless of light intensity, processes with shorter harvesting cycles tend to have a smaller environmental impact compared to processes with longer harvesting cycles. Overall, this research contributes a nuanced and realistic perspective, fostering informed decision-making in sustainable algae cultivation practices, with implications for renewable energy and valuable compound production.
]]>Fermentation doi: 10.3390/fermentation10030162
Authors: Sharli Jodhani Joseph Sebastian Jangho Lee Kaushik Venkiteshwaran Hyung-Sool Lee Virender Singh Banu Ormeci Abid Hussain
Acidogenic fermentation is an emerging biotechnology that allows for the utilization of food waste as a feedstock to produce high-value products such as short-chain fatty acids (SCFAs), effectively offering a tangible solution for food waste management as well as resource recovery. The objectives of the current study were to identify the ideal inoculum, waste-activated sludge (WAS) or anaerobic digester sludge (AD), for the acidogenic fermentation of food waste at room temperature, as well as to evaluate the impact of heat pretreatment of these inoculums on fermentation performance. The maximum hydrolysis yield of 399 g sCOD/kg VS added was obtained when untreated AD was used as the inoculum, whereas the pretreated AD inoculum provided the highest SCFA yield and conversion efficiency of 238 g sCODSCFA/kg VS added and 71%, respectively. Heat pretreatment had a detrimental impact on the WAS inoculum, leading to lower hydrolysis and SCFA yields, but exerted a positive influence on the AD inoculum. The microbial community showed that heat pretreatment negatively impacted the abundance of non-spore-forming hydrolytic and acidogenic microorganisms. Overall, this study demonstrates the critical role of inoculum type and heat pretreatment in optimizing the acidogenic fermentation process, laying the groundwork for future refinements in SCFA production from food waste through inoculum design.
]]>Fermentation doi: 10.3390/fermentation10030161
Authors: Hironaga Akita Shodai Shibata Tomoe Komoriya Shinnosuke Kamei Hiromichi Asamoto Masakazu Matsumoto
Each year, near 40 million tons of banana peels are discarded around the world. This plant biomass could potentially be utilized for energy production. Simultaneous saccharification and fermentation (SSF) is an effective method for producing biofuels from plant biomasses. Since SSF with enzymatic hydrolysis and fermentation are performed simultaneously in the same reactor, the production process is simpler than most existing methods. Here, we describe isobutanol production using SSF with hydrothermally treated banana peel samples and an Escherichia coli strain able to utilize glucose and xylose to produce isobutanol. To enhance the glucose and xylose concentrations, the reaction conditions for the enzymatic hydrolysis of plant biomass using two kinds of saccharification enzymes were optimized, including the enzyme unit ratio, reaction temperature and sample gram. When the optimized conditions for enzymatic hydrolysis were applied to SSF, the glucose and xylose produced from the hydrothermally treated samples were consumed, producing isobutanol. Moreover, the isobutanol concentration increased with an increasing initial culture pH, reaching 1.27 g/L at pH 6.5, which was consistent with the optimal initial culture pH for isobutanol production by this E. coli strain. Taken together, these results indicate that the established method is potentially useful for industrial isobutanol production.
]]>Fermentation doi: 10.3390/fermentation10030160
Authors: Shanyue Guan Chao He Pengfei Li Panpan Li Tingting Hou Zan Gao Gang Li Youzhou Jiao
Biological pretreatment can promote the degradation of biomass and enhance methane production via the subsequent anaerobic digestion. In addition, a large amount of bio-heat can be generated during the pretreatment process to provide heat for the anaerobic digestion process. In this study, composite microorganisms were employed for pretreating corn straw. The impact of different pretreatment times and the heat generated by the pretreatment process on subsequent anaerobic digestion were studied. The results show that the maximum temperature of the pretreatment process was 56.2 °C, obtained on day 6. After 14 days of pretreatment, the degradation rate of the pretreatment group increased by 41% compared with the control group. As a consequence, straws with different pretreatment times were used for anaerobic digestion. The group that underwent 6 days of pretreatment and utilized bio-heat generated from pretreatment achieved the highest cumulative methane production of 401.58 mL/g VS, which was 60.13% higher than in the control group without pretreatment. After 6 days of composite microorganism pretreatment, the group that utilized bio-heat achieved a 29.08% increase in cumulative methane production compared to the group that did not utilize bio-heat. In conclusion, this study highlights the potential of biological pretreatment with composite microorganisms followed by anaerobic digestion using bio-heat as an effective method for treating corn straw.
]]>Fermentation doi: 10.3390/fermentation10030159
Authors: Najet Mouguech Patricia Taillandier Jalloul Bouajila Regine Basseguy Mehrez Romdhane Naceur Etteyeb
This study aimed to investigate the influence of galvanized steel coupons on black tea kombucha fermentation. As a secondary objective, the corrosion activity of the fermented medium at different stages of fermentation was investigated. The results revealed significant interactions among microorganisms, the metal, and the fermented medium. On one hand, mass loss measurement, scanning electron microscopy (SEM) analysis, and released zinc and iron ion analysis showed the deterioration of galvanized steel coupons. On the other hand, HPLC-RI analysis showed that the presence of steel coupons improved the kinetics of fermentation. The chemical composition and bioactivity of kombucha were also influenced by the presence of galvanized steel. The results showed the detection of eleven phenolic compounds by HPLC-DAD, including trihydroxyethylrutin, methyl 3,5-dihydroxybenzoate, and ethyl 4-hydroxy-3-cinamate, which were found only in kombucha in the presence of galvanized steel (K+GS). In addition, a total of 53 volatile compounds were detected by GC-MS before and after derivatization, including eleven constituents identified for the first time in K+GS. Concerning antioxidant activity, a higher percentage of inhibition against the DPPH radical was attributed to the ethyl acetate extract found in K+GS (IC50 = 8.6 µg/mL), which could suggest the formation of inhibitors. However, according to the electrochemical findings, the corrosion current density increased threefold during the fermentation process compared to acidified black tea, indicating that corrosion activity was promoted in the kombucha medium and suggesting several competing phenomena between corrosion and inhibition.
]]>Fermentation doi: 10.3390/fermentation10030158
Authors: Wen He Dahai Zhang Lu Zhang Zhuanyi Ai Zechong Guo Tongyi Yang Linzhi Zhai Cheng Huang
The integration of a microbial electrolysis cell (MEC) is an effective strategy for enhancing the efficiency and stability of an anaerobic digestion (AD) system for energy recovery from waste-activated sludge (WAS). Typically, electrodes are arranged as separate components, potentially disrupting mixing and complicating the reactor configuration, posing challenges for the scaling up of AD-MEC coupling systems. In this study, electrodes were introduced into a continuous stirring tank reactor (CSTR) in a “stealth” manner by integrating them with the inner wall and stirring paddle. This electrode arrangement approach was validated through a sequential batch digestion experiment, resulting in a remarkable 1.5-fold increase in cumulative methane production and a shortened lag period compared to the traditional CSTR with a nonconductive inner wall and stirring paddle. Both the conductive materials (CMs) employed in the electrodes and the electrochemical processes equally contributed to the observed enhancement effect of the electrodes by regulating the evolution of the microbial community within the electrode biofilms, with a specific emphasis on the enrichment of methanogens (primarily Methanobacterium). This research offers a potential avenue to solve the contradiction between the electrode introduction and the mixing operation in AD-MEC coupling systems and to contribute to its future commercial application.
]]>Fermentation doi: 10.3390/fermentation10030157
Authors: Han Wang Yanjing Li Yifei Wang Ting Shi Bo Wang
Penicillium is a kind of common filamentous fungi yielding high levels of secondary metabolites with diverse structures and attractive activities. Among these fungi, Penicillium janthinellum is a potential producer of secondary metabolites whose natural products have been noticed due to their various chemical structures and biological activities. This review summarizes the sources, distribution, bioactivities and structural characteristics of compounds isolated from P. janthinellum from 1980 to 2023. A total of 153 natural products have been isolated from P. janthinellum, of which 65 were new compounds. The compounds separated from P. janthinellum exhibit diverse skeletal chemical structures, concentrated in the categories of polyketides (40%), alkaloids (31%) and terpenoids (14%). P. janthinellum-derived compounds display attractive biological activities, such as cytotoxic, antibacterial, antifungal and antiviral activities. These results indicate that P. janthinellum is a potential fungus for producing bioactive secondary metabolites which can be used as precursors for new drugs.
]]>Fermentation doi: 10.3390/fermentation10030156
Authors: Annika Tyszak Lars Rehmann
Clostridia are interesting candidates for biotechnological applications due to their diverse and unique metabolic abilities. Particularly in continuous fermentation processes, productivity-decreasing metabolic oscillations have been reported in many species. The resulting process instability and reduced productivity can be a serious hurdle for the development of industrially feasible processes. This review highlights the current state of knowledge about oscillatory metabolic phenomena in Clostridia, including the mechanisms, assumed and proven, behind those oscillations and methods to mitigate the phenomena if applicable. The nature of observed metabolic oscillations in Clostridia is diverse, including a wide range of periods of oscillation and different parameters in which the oscillation is observed. Some phenomena remain to be investigated further, while others are already well understood. However, knowledge of mechanisms is a very valuable asset in overcoming the metabolic oscillation to create a stable process.
]]>Fermentation doi: 10.3390/fermentation10030155
Authors: Antonela Marquez Matías Russo Carlos Tomei Patricia Castellano Edoardo Puglisi Roxana Medina Paola Gauffin-Cano
The administration of goat milk fermented (FGM) with Lactobacillus delbrueckii subsp. indicus CRL1447 and supplemented with different mixes of lactobacilli strains (Mix1: Limosilactobacillus fermentum CRL1446 + Lactiplantibacillus paraplantarum CRL1449 + Lactiplantibacillus paraplantarum CRL1472; Mix2: CRL1446 + CRL1449; Mix3: CRL1446 + CRL1472; and Mix4: CRL1449 + CRL1472) was investigated regarding body weight, metabolic and inflammatory parameters, and gut microbiota (GM) composition in mice fed a high-fat diet (HFD). Body weight gain, adipocyte size, fasting blood glucose, serum triglyceride, and leptin levels were significantly reduced in the group fed FGM+Mix3 compared with the obese mice fed FGM. FGM+Mix2 and FGM+Mix3 modified the GM composition, reversing the dysbiosis caused by the HFD. Although there were no significant changes at the phylum level, the GM composition was significantly changed at the family and genus levels. Results suggest that the administration of FGM+Mix3 improves metabolic and immune profiles in obese mice while positively modulating the GM, therefore attenuating the risk factors associated with obesity.
]]>Fermentation doi: 10.3390/fermentation10030154
Authors: Zhixin Yu Hongxin Fu Jufang Wang
4′-N-demethyl-vicenistatin is a vicenistatin analogue that has better antitumor activity with promising applications in the pharmaceuticals industry. The harnessing of the complete potential of this compound necessitates a systematic optimization of the culture medium to enable the cost-effective production of 4′-N-demethyl-vicenistatin by Streptomyces parvus SCSIO Mla-L010/ΔvicG. Therefore, in this study, a sequential approach was employed to screen the significant medium compositions, as follows: one-factor-at-a-time (OFAT) and Plackett–Burman designs (PBD) were initially utilized. Cassava starch, glycerol, and seawater salt were identified as the pivotal components influencing 4′-N-demethyl-vicenistatin production. To further investigate the direct and interactive effects of these key components, a three-factor, five-level central composite design (CCD) was implemented. Finally, response surface methodology (RSM) and an artificial-neural-network-genetic-algorithm (ANN-GA) were employed for the modeling and optimization of the medium components to enhance efficient 4′-N-demethyl-vicenistatin production. The ANN-GA model showed superior reliability, achieving the most 4′-N-demethyl-vicenistatin, at 0.1921 g/L, which was 17% and 283% higher than the RSM-optimized and initial medium approaches, respectively. This study represents pioneering work on statistically guided optimization strategies for enhancing 4′-N-demethyl-vicenistatin production through medium optimization.
]]>Fermentation doi: 10.3390/fermentation10030153
Authors: Dingxuan He Dingyu Duan Xueyan Lv Baihui Xiong Zhuojia Li Shaojun Zhang Jing Cai Xinrong Qiao Qiong Chen
Objective: The aim of this study was to optimize the fermentation process of Radix Ranunculi ternate via microbial fermentation and analyze the changes in the contents of the main components, the antioxidant and hypoglycemic capacities of the extract before and after fermentation. Methods: The solid-state fermentation process was optimized using single-factor tests and the response surface method, with the yield of the alcohol extract of R. ternate as an evaluation index. Results: The best fermentation process was optimized using solid-state endophytic fungus fermentation technology as follows: strain addition ratio of Chaetomium globosum/Fusarium equiseti = 1:1, fermentation for 5 d, sieve size of 40 mesh, liquid/material ratio of 0.8:1 mL·g−1, fermentation temperature of 31 °C, and inoculation amount of 7.5%. Under the optimized conditions, the contents of the water-soluble extract and total polysaccharides decreased by 12.71% and 12.95%, respectively. In the fermentation, the contents of the ethanol-soluble extract, flavonoids, saponins, polyphenols, organic acids, and total amino acids of the fermented R. ternate increased by 19.77%, 57.14%, 79.67%, 14.29%, 17.63%, and 3.82%, respectively. The scavenging rate for DPPH, ABTS+, and ·OH free radicals and inhibitory rate for α-amylase of the fermented R. ternate also increased by 19.02%, 14.17%, 7.53%, and 34.54%, respectively, compared with the unfermented R. ternate. Conclusions: Solid-state fermentation opens new avenues for the development and application of R. ternate as a natural antioxidant and hypoglycemic food.
]]>Fermentation doi: 10.3390/fermentation10030152
Authors: Xiaoying Yang Shan Xiao Jihui Wang
In some countries, yeasts are still not allowed in the production of commercially fermented sausages. Therefore, further research is needed on producing fermented meat products using different strains of yeasts. In this study, two strains of Debaryomyces hansenii (D. hansenii Y61 and Y67) were inoculated in fermented sausages to study their effects as starter cultures. The inoculation of D. hansenii strains affected ripening by decreasing the pH and aw. The sausages inoculated with Y61 and Y67 exhibited decreases in lipid oxidation of 40.70% and 36.04%, respectively, and Enterobacteriaceae counts of 50% and 100%, respectively. The inoculating yeasts Y61 and Y67 increased the lightness (L*) and redness (a*) of fermented sausages. The D. hansenii-inoculated sausages had higher levels of free amino acids and fatty acids, which improved the digestibility, sensory value, and safety of these sausages. Moreover, the total amount of ester compounds increased by 87.14% and 83.31% in the Y61- and Y67-inoculated groups, respectively, which contributed to the aroma. Better sensory attributes were also found in the sausages inoculated with Y61 and Y67 D. hansenii. Native D. hansenii Y61 and Y67 are, therefore, good starter cultures for fermented sausage production. Together, the results provide data supporting future research and the use of yeast-fermented sausages.
]]>Fermentation doi: 10.3390/fermentation10030151
Authors: Jingran Ding Feng Zhen Xiaoying Kong Yunzi Hu Yi Zhang Lang Gong
Biochar has attracted increasing attention as an additive for enhancing the performance of anaerobic digestion (AD), but the effect of biochar on microbial regulatory mechanisms in enhancing AD performance is unclear. To investigate how biochar modulates the process of AD, different inoculum sources including cellulose–peptone–swine inoculum (CPI) and swine manure inoculum (SMI) were designed to determine the effect of biochar on the performance and microbial communities of anaerobic digestion of the feedstock concentration from 1 to 6%. The results showed that the methane yields of CPI seeds were higher 20.3–38.7% than those of SMI seeds without a biochar addition, whereas the biochar addition reduced 5.3 and 23.1% of the corresponding methane yield of CPI and SMI, respectively. The biochar enhances the accumulation of volatile fatty acids (VFAs) and weakens the potential ammonia inhibition by adsorption, and it can improve the degradation rate of organic content of soluble COD for different inoculum sources. Microbial community analyses showed that the biochar addition could facilitate the growth of Bacteroidetes and Clostridiales, and it enriched the relative abundance of hydrogenotrophic methanogens Methanobrevibacter and Methanobacterium. Overall, although the modulation of biochar possessed different effects on the anaerobic digestion performance, it contributed to the stability and degradation efficiency of the digestion system. The recycling implication of biochar is critical to realizing a low-carbon and renewable treatment system for organic wastes.
]]>Fermentation doi: 10.3390/fermentation10030150
Authors: Iulia-Roxana Angelescu Medana Zamfir Emanuela-Cătălina Ionetic Silvia-Simona Grosu-Tudor
Lactobacillus helveticus 34.9 was isolated from a sample of Romanian home-made fermented milk, producing both surface layer proteins and a class III bacteriocin. The present study aimed to investigate the biological and functional role of the S-layer in correlation with its probiotic properties. The presence of S-layer proteins resulted in various degrees of co-aggregation of L. helveticus 34.9 with pathogens and with other lactic acid bacteria, but the removal of these proteins reduced the co-aggregation with all the tested strains. Moreover, the S-layer proved to be involved in cell wall hydrophobicity and cellular protection during freeze-drying. In the simulated passage through the gastrointestinal tract, S-layer depleted cells exhibited increased vulnerability, with greater viability loss in low pH and pepsin treatment compared to control cells. Subsequently, in the small intestine simulation, these cells lost all viability, underscoring the vital role of extracellular proteins for cell protection. The morphological effects of these treatments were observed by scanning electron microscopy. Severe structural damage was noticed when the S-layer was absent, including loss of cell shape and integrity as well as many ghost cells emptied of their content. Finally, the elimination of surface proteins reduced the interaction between L. helveticus 34.9 and mammalian cells.
]]>Fermentation doi: 10.3390/fermentation10030149
Authors: Raissa Gabriela Martins Reis Barroso Mônica Caramez Triches Damaso Fabricio Machado Sílvia Belém Gonçalves
Lactic acid bacteria are widely used because they produce lactic acid naturally, are resistant to acidic pH and a wide temperature range, and frequently produce lactic acid as a primary metabolite. In this study, Enterococcus durans isolated from buffalo milk was employed in lactic acid fermentation with the primary goal of obtaining fermentation parameters for an effective process enabling the use of lactose as an alternative carbon source. Fermentative parameters such as initial concentration of carbon source, dissolved oxygen concentration, cell recycling, and batch with pulse operation mode were studied to find the best conditions for L-(+)-lactic acid production. The association of 20 g·L−1 of lactose with 10 g·L−1 of glucose enabled the best bioconversion to lactic acid. Anaerobiosis did not contribute to increasing lactic acid production. Batch fermentation with cell recycling was the strategy that enhanced lactic acid production and lactose consumption, reaching 26.07 g·L−1, 0.36 g·L−1·h−1 of productivity and yielding about 0.86 g·g−1. It is fundamental to evaluate the parameters of lactic acid fermentation and provide efficient and sustainable production methods.
]]>Fermentation doi: 10.3390/fermentation10030148
Authors: Simona Guerrini Viola Galli Silvia Mangani Lisa Granchi
Low-temperature treatments can be applied to grapes or must before alcoholic fermentation to enhance the wine’s sensory characteristics. Several studies have shown that such practices have a positive effect on the polyphenol profile of the wine, but only a few surveys have examined the effect of these treatments on the yeast microbiota of grapes and wine. Therefore, this study aimed to evaluate how cryoextraction (freezing the grape with liquid nitrogen) and cold pre-fermentative maceration (at 5 °C for 48 h) affect the Saccharomyces and non-Saccharomyces populations during the winemaking process of red grapes, cv Sangiovese, conducted at two temperatures (20 and 30 °C). This research analyzed the concentration of various yeast species, their fermentation abilities, and the resulting wine’s aromatic profile. The Principal Component Analysis performed on yeast concentrations during the fermentations of various wines did not group the experimental wines based on treatment. However, the same groupings were highlighted when the concentrations of the volatile compounds, quantified in the experimental wines, were processed using the same statistical approach. Therefore, cryoextraction and cold pre-fermentative maceration seem to contribute less to the aromatic profile than the yeasts involved in the fermentation process.
]]>Fermentation doi: 10.3390/fermentation10030147
Authors: Sandra Consuelo Martínez-Estrada José Alberto Narváez-Zapata Raúl Rodríguez-Herrera Julio Grijalva-Ávila José Natividad Gurrola-Reyes Claudia Patricia Larralde-Corona Isaías Chairez-Hernández
Durango State has the denomination of origin for the production of mezcal, which is made from Agave durangensis, mainly in an artisanal way; therefore, differences in the fermentation process affect the quality of the final product. The main objective of the present study was to evaluate the diversity of culturable yeasts involved in the artisanal and semi-technified process of mezcal production in the State of Durango. Three distilleries with different production processes were monitored at different fermentation stages (beginning, mid-fermentation, and end of fermentation) in the spring and summer seasons. A greater diversity was found in the distillery of Nombre de Dios in both the spring and summer production seasons (H’ = 1.464 and 1.332, respectively), since it maintains an artisanal production process. In contrast, the distillery of Durango, where a Saccharomyces cerevisiae commercial inoculum is used to start fermentation, presented low diversity indexes (H’ = 0.7903 and 0.6442) and only S. cerevisiae, Kluyveromyces marxianus, and, sporadically, Pichia manshurica were found. Results suggest that the yeast microbiota involved in mezcal fermentation during the different seasons is affected by the type of inoculum; changes include the presence of some species that were only identified during a specific season in alcoholic fermentation, such as Torulaspora delbrueckii and Pichia kluyveri.
]]>Fermentation doi: 10.3390/fermentation10030146
Authors: Yiyun Huang Jingwen Zhou Jianghua Li Guocheng Du Jian Chen Xinrui Zhao
Leghemoglobin (LegH) is a plant-derived hemoglobin that can be used as a food additive to confer red color and meat flavor to plant-based meat products. Although LegH has been expressed in Saccharomyces cerevisiae, the productivity is low at the shaking-flask level, and the downstream process of purification is complicated. Herein, the intracellular expression of LegH reached 151.2 mg/L through initial promoter modification. Then, the fermentation strategy was optimized, and the titer of LegH reached 544.8 mg/L (5.2 mg/L/OD600 per unit yield) in the two-stage fed-batch fermentation in a 5-L fermenter. After the modification of signal peptide and knockout of proteases, the secretory expression of LegH was achieved in recombinant S. cerevisiae, and the final secretory titer of LegH reached 88.5 mg/L at the 5-L fermenter level. Based on the results of this study, the secreted LegH can be widely applied in the fields of food processing and biocatalysis in the future.
]]>Fermentation doi: 10.3390/fermentation10030145
Authors: Yutthana Kingcha Laphaslada Pumpuang Saowalak Adunphatcharaphon Kanittha Chantarasakha Pannita Santiyanont Manadsaree Klomtun Thitiphorn Janyaphisan Kittima Kongtong Natthaporn Phonsatta Atikorn Panya Wonnop Visessanguan Awanwee Petchkongkaew Weerapong Woraprayote
The suitability of Lactiplantibacillus plantarum (L. plantarum) as a functional starter culture in Nham fermentation was investigated, with a focus on evaluating both its probiotic attributes and fermentation capability. L. plantarum BCC 4352 (LpbBCC4352) exhibited colony-associated antimicrobial activity against Kocuria rhizophila, L. plantarum, Latilactobacillus sakei ssp. sakei, and Pediococcus pentosaceus, as well as the zoonotic Streptococcus suis. LpbBCC4352 exhibited impressive acid (pH 2.5) and bile resistance, coupled with notable survival rates in a simulated human digestive model. In addition, the strain is able to utilize fructo-oligosaccharides in simulated human colon conditions. It also displayed robust adhesion to human colon cell monolayers (Caco-2) and gastric mucin. Furthermore, it showed a promising cholesterol reduction ability in the fermentation medium. The safety of LpbBCC4352 for human consumption was confirmed through a hemolytic activity assay and antibiotic susceptibility testing. Moreover, using LpbBCC4352 as a starter culture not only enhanced the firmness of Nham but also ensured consumer satisfaction. The overall findings emphasize the potential use of LpbBCC4352 as a safe and effective functional starter culture, particularly in the production of Nham.
]]>Fermentation doi: 10.3390/fermentation10030144
Authors: Aleksandra Katanski Vesna Vučurović Damjan Vučurović Bojana Bajić Žana Šaranović Zita Šereš Siniša Dodić
The present work highlights the advances of integrated starch and bioethanol production as an attractive industrial solution for complex wheat exploitation to value-added products focusing on increased profitability. Bioethanol is conventionally produced by dry-milling wheat grain and fermenting sugars obtained by the hydrolysis of starch, while unused nonfermentable kernel compounds remain in stillage as effluents. On the other hand, the wet-milling of wheat flour enables complex wheat processing for the simultaneous production of starch, gluten, and fiber. The intermediates of industrial wheat starch production are A-starch milk, containing mainly large starch granules (diameter > 10 μm), and B-starch milk, containing mainly small starch granules (diameter < 10 μm). The present study investigates different starch hydrolysis procedures using commercial amylase for bioethanol production from A-starch and B-starch milk by batch fermentation using distillers’ yeast Saccharomyces cerevisiae Thermosacc®. Cold hydrolysis with simultaneous liquefaction and saccharification at 65 °C, a pH of 4.5, and a duration of 60 min was the most efficient and energy-saving pretreatment reaching a high conversion rate of starch to ethanol of 93% for both of the investigated substrates. A process design and cost model of bioethanol production from A-starch and B-starch milk was developed using the SuperPro Designer® v.11 (Intelligen Inc., Scotch Plains, NJ, USA) software.
]]>Fermentation doi: 10.3390/fermentation10030143
Authors: Fernanda Maria Rosa Thaís Fernandes Mendonça Mota Cleverson Busso Priscila Vaz de Arruda Patrícia Elena Manuitt Brito João Paulo Martins Miranda Alex Batista Trentin Robert F. H. Dekker Mário Antônio Alves da Cunha
The industrial sector plays a significant role in global economic growth. However, it also produces polluting effluents that must be treated to prevent environmental damage and ensure the quality of life for future generations is not compromised. Various physical, chemical, and biological methods have been employed to treat industrial effluents. Filamentous fungi, in particular, have garnered attention as effective bioremediation agents due to their ability to produce enzymes capable of degrading recalcitrant compounds, and adsorb different pollutant molecules. The novelty of the work reported herein lies in its comprehensive assessment of the research surrounding the use of white- and brown-rot fungi for removing phenolic compounds from industrial effluents. This study employs a systematic review coupled with scientometric analysis to provide insights into the evolution of this technology over time. It scrutinizes geographical distribution, identifies research gaps and trends, and highlights the most studied fungal species and their applications. A systematic review of 464 publications from 1945 to 2023 assessed the use of these fungi in removing phenolic compounds from industrial effluents. White-rot fungi were predominant (96.3%), notably Phanerochaete chrysosporium, Pleurotus ostreatus, Trametes versicolor, and Lentinula edodes. The cultures employing free cells (64.15%) stand out over those using immobilized cells, just like cultures with isolated fungi regarding systems with microbial consortia. Geographically, Italy, Spain, Greece, India, and Brazil emerged as the most prominent countries in publications related to this area during the evaluated period.
]]>Fermentation doi: 10.3390/fermentation10030142
Authors: Nasib Qureshi Richard D. Ashby Nancy N. Nichols Ronald Hector
Butyric acid, a four-carbon fatty acid, is an important industrial chemical and feedstock. To produce this chemical, a control fermentation was run with a 126.5 g.L−1 glucose concentration in the feed medium. In this medium, the strain produced 44.8 g.L−1 total acid with a productivity of 0.23 g.L−1h−1 and a yield of 0.41 g.g−1. The strain (Clostridium tyrobutyricum ATCC 25755) was also able to utilize glucose and xylose simultaneously with similar fermentation performance. The culture was also used to produce butyric acid from wheat straw hydrolysate (WSH) employing a hot water pretreatment. In a batch system, the strain resulted in a productivity and yield of 0.27 g.L−1h−1 and 0.44 g.g−1, respectively, which was an improvement over the use of glucose or xylose alone or mixtures of both. To improve reactor productivity, a membrane cell recycle bioreactor was used which resulted in a productivity of 1.89 g.L−1h−1. This productivity was 822% of that achieved in the glucose or xylose batch fermentation. Furthermore, a butyric acid recovery method was developed using XAD-4 adsorbent resin. In this system, up to 206.1 g.L−1 of butyric acid was used in the feed and, as a result of the quick adsorption, the residual butyric acid concentration was 29.5 g.L−1. In this experiment, the rate of acid removal of 1059.4 g.L−1h−1 was achieved.
]]>Fermentation doi: 10.3390/fermentation10030141
Authors: Marcela Moreira Albuquerque Walter Jose Martinez-Burgos Gabriela De Bona Sartor Luiz Alberto Junior Letti Júlio Cesar De Carvalho Carlos Ricardo Soccol Adriane Bianchi Pedroni Medeiros
Palm oil, the main vegetable oil produced globally, serves diverse purposes, ranging from cooking to the production of processed foods, cosmetics, and biodiesel. Despite contributing significantly to the economies of major producing nations, the escalating production of palm oil raises serious environmental concerns, including deforestation, biodiversity loss, and various forms of pollution. Palm oil mill effluent (POME), a byproduct of palm oil extraction, poses a severe environmental threat when left untreated. As an eco-friendly alternative, anaerobic digestion in controlled bioreactors has emerged, offering simultaneous POME treatment and biofuel generation, particularly hydrogen, with high energy efficiency. This review explores the challenges and opportunities associated with biohydrogen production from POME. Key considerations involve optimizing parameters through pretreatments, nanoparticle incorporation, defining optimal bioreactor conditions, determining hydraulic retention times, and integrating multi-stage processes like dark fermentation followed by photofermentation. This review also emphasizes the significance of sustainable practices and economic analyses in shaping the future of hydrogen production from POME, positioning it as a pivotal player in the palm oil industry’s circular economy and the global energy transition.
]]>Fermentation doi: 10.3390/fermentation10030140
Authors: Yilan Shao Yifan Bai Zhehui Cai Nan Pu Huawei Zhang
To improve the yield of the therapeutic agent N-methylsansalvamide (SA), optimization of stationary liquid fermentation conditions was conducted on an endophytic strain, Fusarium sp. R1, at flask level. Using a One-Factor-At-a-Time approach, the fermentation conditions for SA production were determined as follows: fermentation time of 13 d, 24 °C, initial pH of 6.5, seed age of 24 h, inoculum size of 5.0% (v/v), loading volume of 50% (v/v), and 20.0 g/L salinity. Sucrose, tryptone, and yeast extract were found to be the best sources of carbon and nitrogen. Using response surface methodology, the optimal medium compositions consisted of 22.5 g/L sucrose, 16.5 g/L tryptone, and 0.024 g/L yeast extract. Verification tests suggested that the SA yield under these optimal conditions reached up to 536.77 ± 2.67 mg/L, which was increased by almost ten times the initial yield (54.05 ± 3.45 mg/L). The findings indicate that a high SA production yield can be achieved by stationary culture of strain R1 under proper fermentation conditions using a low-cost medium. This study paves the way toward industrial-scale SA production by strain R1 for new drug development.
]]>Fermentation doi: 10.3390/fermentation10030139
Authors: Scheherazed Dakhmouche Djekrif Amel Ait Kaki El Hadef El Okki Leila Bennamoun Abdelhak Djekrif Tahar Nouadri Louisa Gillmann
Protease-producing yeasts were isolated from potato wastes and screened for protease production on skim milk agar plates. The best producer of protease isolate was identified as Clavispora lusitaniae. The strain showed higher enzyme production using tomato pomace and bread waste mix as a solid fermentation substrate. The optimized conditions improved enzyme activity and showed a maximal production of 33,450 ± 503 IU/g compared with the initial activity of 11,205.78 ± 360 without medium optimization. A threefold increase in protease activity after medium optimization proved the reliability of using the PBD and CCD design. A 19.76-fold purified enzyme and a yield of 32.94% were obtained after purification. The protease showed maximum activity at pH 4 and 60 °C and was resistant to Tween 20, Tween 80, SDS, and β-mercaptoethanol, Ca2+, and Mg2+ stimulated it. The protease activity was strongly inhibited in the presence of urea, and EDTA. The results revealed Clavispora lusitaniae protease’s ability to degrade wheat seeds and flour gluten by 98.7% and 97% respectively under pH 4 for 24 h at 40 °C. According to this study, this enzyme could be a potential candidate for the food industry, particularly for treating wheat seed and flour to reduce the immunogenicity of gluten.
]]>Fermentation doi: 10.3390/fermentation10030138
Authors: Christina N. Economou Georgios Manthos Dimitris Zagklis Michael Kornaros
Biological treatment is a promising alternative for waste management considering the environmentally sustainable concept that the European Union demands. In this direction, anaerobic digestion comprises a viable waste treatment process, producing high energy-carrier gases such as biomethane and biohydrogen under certain operating conditions. The mathematical modeling of this bioprocess can be used as a valuable tool for process scale-up with cost-effective implications. The scope of this work was the evaluation of the well-established Anaerobic Digestion Model 1 (ADM1) for use in two-stage anaerobic digestion of agro-industrial waste. Certain equations for the description of the metabolic pathways for lactate and bioethanol accumulation were implemented in the existing mechanistic model in order to enhance the model’s accuracy. The model presents a high estimation ability regarding the final product (H2 and biogas) reaching the same maximum value for the theoretical as the experimental data of these products (0.0012 and 0.0036 m3/d, respectively). The adapted ADM1 emerges as a useful instrument for designing anaerobic co-digestion processes with the goal of achieving high yields in fermentative hydrogen production, considering mixed biomass growth mechanisms.
]]>Fermentation doi: 10.3390/fermentation10030137
Authors: Marianne Hull-Cantillo Mark Lay Graeme Glasgow Peter Kovalsky
Much emphasis has been given to algal biomass growth in dairy farm wastewater. Most of the systems examined require productive land to be converted and/or freshwater use to dilute high concentrations of nutrients found in dairy effluent. A rotating algal biofilm (RABR) provides the capacity to grow algae without sacrificing productive land or freshwater. In theory, this system would overcome some of the economic and environmental challenges that other systems have. A combination of theoretical information, nutrient uptake formulas, and economic formulas were used to calculate the potential of biogas production from algae grown in an RABR with dairy effluents. The average nutrient uptake was 0.8 mgN/m2 per day and 0.1 mgP/m2 per day. The maximum methane production from the anaerobic digestion of algae was 112 m3/RABR·year. The minimum and maximum economic scenarios resulted in gross profits of NZD −2101 and −1922. After evaluating this system for the first time in the New Zealand dairy farming context, it was found that biogas production from an RABR is not a feasible option for New Zealand dairy farmers.
]]>Fermentation doi: 10.3390/fermentation10030136
Authors: Alice Jaeger Laura Nyhan Aylin W. Sahin Emanuele Zannini Elke K. Arendt
Brewer’s spent yeast (BSY) is a plentiful by-product of the brewing process. Currently regarded as a waste product, this low-value material is used in animal feed formulations or disposed of. However, BSY is known to be nutritionally dense, particularly regarding high-quality proteins, fibre, vitamins, and minerals. Previous work has examined the effect of a process including fermentation with Lactobacillus amylovorus FST 2.11 on BSY and indicates a reduction in bitterness intensity and an increase in sour and fruity flavours. The current study expands on this previous work, examining the changes in composition and functionality resulting from this upcycling process. The major changes include protein degradation and a decrease in pH, leading to increased protein solubility by 41%, increased foam stability by up to 69% at pH 7, and improved emulsion stabilising characteristics as well as differences in rheological behaviour during heating. Compositional changes are also detailed, with evidence of glucan and trehalose degradation. These changes in the physical and functional properties of BSY provide useful information, particularly with regard to the incorporation of BSY into food products for human consumption.
]]>Fermentation doi: 10.3390/fermentation10030135
Authors: Tim Granata Bernd Rattenbacher Florian Kehl Marcel Egli
Microbial factories, including microalgae biofactories, have the enormous potential to produce biochemicals for manufacturing diverse bioproducts. A strategic approach to biofactories is maintaining cultures in bioreactors with sufficient resource inputs to optimize biochemical precursors for manufacturing bioproducts. Exploiting synergies that use the waste output from a bioreactor containing one microbial culture as a resource input to another bioreactor with a different microbe can lead to overall efficiencies in biofactories. In this paper, two synergies are evaluated. The first is between yeast and algae bioreactors, where data are presented on oxygen (O2) uptake by aerobic yeast cultures and their production of carbon dioxide (CO2) and the uptake of CO2 by algae and their production of O2. The second focuses on a carbon capture reactor, which is utilized to increase CO2 levels to promote higher algal production. This approach of waste as a resource for bioreactor cultures is a novel synergy that can be important to bioreactor designs and, ultimately, to the production of bioproducts.
]]>Fermentation doi: 10.3390/fermentation10030134
Authors: Yuri Kikuchi Daichi Kanai Kenjiro Sugiyama Katsuhiko Fujii
Although biogas is a renewable energy source alternative to natural gas, it contains approximately 40 vol% CO2 and, hence, a low calorific value. The sequestration of CO2 from biogas is, therefore, essential before its widespread use. As CO2 can be easily solubilized as carbonate and bicarbonate in alkaline water, in this study, we isolated and characterized alkaliphilic wild microalgae that grow under high-level CO2 conditions and evaluated their application potential in CO2-removal from biogas. For this purpose, freshwater samples were enriched with 10 vol% CO2 and an alkaline culture medium (pH 9.0), wherein almost free CO2 was converted to carbonate and bicarbonate to yield alkaliphilic and high-level CO2-tolerant microalgae. Ten microalgal strains of Micractinium, Chlorella, Scenedesmus/Tetradesmus, or Desmodesmus spp. were isolated, some of which demonstrated good growth even under conditions of >pH 10 and >30 vol% CO2. All algal strains grew well through fixing biogas-derived CO2 in a vial-scale biogas upgrading experiment, which reduced the CO2 level in biogas to an undetectable level. These strains yielded antioxidant carotenoids, including lutein, astaxanthin, zeaxanthin, and β-carotene, particularly rich in lutein (up to 7.3 mg/g dry cells). In addition, these strains contained essential amino acids, accounting for 42.9 mol% of the total amino acids on average, and they were rich in unsaturated fatty acids (comprising 62.2 wt% of total fatty acids). The present study identified strains that can contribute to biogas upgrading technology, and the present findings suggest that their biomass can serve as useful raw material across the food, nutraceutical, and feed industries.
]]>Fermentation doi: 10.3390/fermentation10030133
Authors: Nazan Tokatlı Demirok Seydi Yıkmış
Watermelon vinegar is a traditional fermented product with antioxidant activity. This study aimed to investigate the antihypertensive and antidiabetic properties of watermelon vinegar treated through ultrasound using the RSM method. We also evaluated the antioxidant activity (CUPRAC and DPPH), bioactive content (total phenolics and total flavonoids), mineral composition, phenolic compounds, α-glucosidase inhibition %, ACE inhibition %, of optimized, and α-amylase inhibition % during 24 months of storage of optimized watermelon vinegar. Optimized antidiabetic and antihypertensive activity was achieved at 6.7 min and 69% amplitude. The optimization of gallic acid was the dominant phenolic in the optimized ultrasound-treated watermelon vinegar (UT-WV) and showed a significant decrease during the 24 months of storage. The lycopene content of the UT-WV concentrate was 8.36 mg/100 mL, 8.30 mg/100 mL, 7.66 mg/100 mL, and 7.35 mg/100 mL after 0, 6, 2, and 24 months of storage, respectively. The levels of ACE inhibitory activity, α-glucosidase inhibitory activity, and α-amylase inhibitory activity decreased significantly (p < 0.05) after 24 months of storage. K, with values of 201.03 ± 28.31, was the main mineral in the UT-WV. Therefore, the bioactive components and the antidiabetic and antihypertensive properties of the UT-WV produced by conventional fermentation were necessary. Therefore, further experimental studies are necessary for a better understanding of the possible and potential health effects of watermelon vinegar.
]]>Fermentation doi: 10.3390/fermentation10030132
Authors: Francesca Melini Valentina Melini
Flavour is a key driver of consumer preferences and acceptability of foods, and the food industry has made food aroma compounds a crucial area of research. At present, about 80% of food aroma compounds are produced by chemical synthesis; however, alternative production approaches have been explored to meet consumers’ demand for “clean label” food products and “natural” aromas. Bio-production of food aroma compounds from vegetable wastes through fermentation has emerged as a promising alternative. This review showed that fungi and yeasts, and also lactic acid bacteria, can be used to produce aroma compounds through the fermentation of vegetable waste. The produced compounds were mostly responsible for sweet, fruity, and floral notes. Other molecules imparting cheesy/buttery, creamy, green, herbal, grass notes were also obtained through the fermentation of vegetable food waste. Substrates varied from agricultural waste such as rice bran to by-products and waste from the fruit supply chain, in particular pomace, peels, pods. During the study, challenges and limitations for the scale-up of the process emerged. The production of aromas is still strongly strain and waste dependent. Certain aspects thus still require attention to avoid that a joint occurrence of technical challenges may cause the failure of the process.
]]>Fermentation doi: 10.3390/fermentation10030131
Authors: Muhammad Uzair Javed Hamid Mukhtar Bartłomiej Zieniuk Umer Rashid
The treatment of living organisms is a critical aspect of various environmental and industrial applications, ranging from wastewater treatment to aquaculture. In recent years, algal-based hollow fiber membrane bioreactors (AHFMBRs) have emerged as a promising technology for the sustainable and efficient treatment of living organisms. This review provides a comprehensive examination of AHFMBRs, exploring their integration with algae and hollow fiber membrane systems for diverse applications. It also examines the applications of AHFMBRs in various areas, such as nutrient removal, wastewater treatment, bioremediation, and removal of pharmaceuticals and personal care products. The paper discusses the advantages and challenges associated with AHFMBRs, highlights their performance assessment and optimization strategies, and investigates their environmental impacts and sustainability considerations. The study emphasizes the potential of AHFMBRs in achieving enhanced nutrient removal, bioremediation, and pharmaceutical removal while also addressing important considerations such as energy consumption, resource efficiency, and ecological implications. Additionally, it identifies key challenges and offers insights into future research directions. Through a systematic analysis of relevant studies, this review aims to contribute to the understanding and advancement of algal-based hollow fiber membrane bioreactors as a viable solution for the treatment of living organisms.
]]>Fermentation doi: 10.3390/fermentation10030130
Authors: Ana Patricia Garza-Chapa Carlos Iván Ávila-Velasco José González-Valdez Alma Gómez-Loredo
Extractive fermentation is an in situ method for the production and recovery of biomolecules of interest. Aqueous two-phase systems (ATPS) allow the product to be recovered in one phase of the system, reducing unit operations in the bioprocess. Thermosensitive polymers such as EOPOs are an interesting alternative to be applied in ATPS. In this work, different EOPOs were tested in an extractive fermentation strategy with the green microalgae Neochloris oleoabundans to provide a basis for future implementations of these systems in microalgae bioprocesses. Extractive fermentations were carried out with two EOPOs of different molecular weights (3900 and 12,000 g/mol) at concentrations of 10% and 15% (w/v). The microalga was incubated axenically under two different sets of conditions for 21 and 45 days, respectively. Cell counts were performed, and cell growth curves were obtained. Additionally, a semi-continuous and batch extractive fermentation assay was performed. The extractive fermentation with EOPO showed lower cell growth and a longer adaptation time of the microalgae in the fermentation, and EPS production yields of up to 8–23 g/L were obtained. Extractive fermentation is an interesting method to be implemented in microalgae cultures; however, further conditions need to be explored to achieve an appropriate bioprocess.
]]>Fermentation doi: 10.3390/fermentation10030129
Authors: Chuyun Zhao Luxin Yang Huan Li Zhou Deng
Acidogenic fermentation can convert food waste (FW) into small molecules of acids and alcohols, and the broth can be used as a carbon source of denitrification in wastewater treatment plants. However, the soluble nitrogen-containing substances generated in fermentation influence the quality of the carbon source, and microbial nitrogen transformation under different pH conditions has rarely been reported. In this study, four FW fermentation systems were operated continuously with a focus on nitrogen transformation, and metagenomic and metatranscriptomic analyses were used to reveal the metabolic pathways. The results showed that approximately 70% of nitrogen existed in solid organic matter, and the dissolution of solid proteins was limited at pH 4.0–5.0. The concentration of soluble nitrogen, encompassing both soluble organic nitrogen and ammonium, remained relatively stable across various pH conditions. However, high pH values promoted the conversion of soluble nitrogen-containing substances to ammonium, and its concentration increased by 122%, 180%, 202%, and 267% at pH 4.00, pH 4.27, pH 4.50, and pH 5.00. Lactobacillus played a crucial role in ammonium production via the arginine deiminase pathway at pH 4.0–4.5, and Prevotella was the key contributor with the assistance of glutamate dehydrogenase at pH 5.0. The findings provide insights into organic nitrogen transformation in acidogenic fermentation for optimizing FW treatment processes.
]]>Fermentation doi: 10.3390/fermentation10030128
Authors: Nicola Ferremi Leali Elisa Salvetti Giovanni Luzzini Andrea Salini Davide Slaghenaufi Salvatore Fusco Maurizio Ugliano Sandra Torriani Renato L. Binati
In this study, two strains of Schizosaccharomyces pombe (NCAIM Y01474T and SBPS) and two strains of Schizosaccharomyces japonicus (DBVPG 6274T, M23B) were investigated for their capacity to ferment apple juice and influence the volatile compounds of cider compared to Saccharomyces cerevisiae EC1118. The ethanol tolerance and deacidification capacity of Schizosaccharomyces yeasts could make them potential substitutes for the commonly used S. cerevisiae starter cultures. Despite different time courses (10–30 d), all strains could complete the fermentation process, and Schizosaccharomyces strains reduced the concentration of malic acid in the apple juice. Results indicated that each yeast exerted a distinctive impact on the volatile profile of the apple cider, giving final products separated using a principal component analysis. The volatile composition of the cider exhibited significant differences in the concentration of alcohols, esters, and fatty acids. Particularly, the flocculant strain S. japonicus M23B increased the levels of ethyl acetate (315.44 ± 73.07 mg/L), isoamyl acetate (5.99 ± 0.13 mg/L), and isoamyl alcohol (24.77 ± 15.19 mg/L), while DBVPG 6274T incremented the levels of phenyl ethyl alcohol and methionol up to 6.19 ± 0.51 mg/L and 3.72 ± 0.71 mg/L, respectively. A large production of terpenes and ethyl esters (e.g., ethyl octanoate) was detected in the cider fermented by S. cerevisiae EC1118. This study demonstrates, for the first time, the possible application of S. japonicus in cider-making to provide products with distinctive aromatic notes”.
]]>Fermentation doi: 10.3390/fermentation10030127
Authors: Jian Sang Hengxian Qu Dong Liu Yunchao Wa Dawei Chen Xia Chen Ruixia Gu Yujun Huang
Alcoholic liver injury is a serious risk to human health. Probiotics have become a popular form of treatment. Lacticaseibacillus casei Grx12 and Limosilactobacillus fermentum Grx07 isolated from the gut of long-lived people in Rugao, Jiangsu, were studied to determine their protective effects and possible mechanisms of action on alcoholic liver injury. The results showed that rat serum ALT and AST were restored, and liver injury was reduced after the probiotics intervention. The level of antioxidant enzymes and antioxidants such as SOD, GSH and GSH-Px in the rat liver was significantly increased (p < 0.05), which reduces the level of MDA, a peroxidation product in the liver, and thus alleviates liver oxidative stress. L. casei Grx12 and L. fermentum Grx07 also could significantly enhance the expression of Nrf2 protein in the rat liver to regulate the anti-oxidative stress response in the body and cells (p < 0.05). The levels of ADH, Na+-K+-ATPase and Ca2+-ATPase in the rat liver were significantly increased (p < 0.05), which enhanced the body’s metabolism of alcohol. The rat serum LPS and liver TNF-α, IL-6, VEGF, TGF-β1 and NF-κB levels were significantly reduced (p < 0.05), indicating that the probiotics could relieve liver inflammation. The results of this study indicate that L. casei Grx12 and L. fermentum Grx07 have certain protective effects on alcoholic liver injury in rats, likely because of their antioxidant properties and ability to prevent oxidative stress and relieve inflammation.
]]>Fermentation doi: 10.3390/fermentation10030126
Authors: Wiem Alloun Cinzia Calvio
The agrifood industry produces copious amounts of waste, which represent an execrable wastage of natural resources and result in economic losses over the entire value chain. This review compares conventional and biological methods for the recovery of functional compounds from plant wastes to rescues part of the intrinsic valuable elements contained therein. Biological methods involve bioprocesses based on hydrolytic enzymes and engineered bacterial strains, to facilitate the release of valuable compounds. Then, this review explores the innovative and transformative role of artificial intelligence and machine learning techniques for real-time monitoring, optimizing, and digitizing the extraction procedures. By combining the potential of biological extraction and AI integration, this review provides insights on how these approaches can revolutionize the agrifood sector, increasing the efficiency and environmental sustainability of the plant waste valorization process.
]]>Fermentation doi: 10.3390/fermentation10030125
Authors: Ronit Yaa’ri Eitan Schneiderman Vicky Ben Aharon Maria Stanevsky Elyashiv Drori
Residual sugars (RS) in wine are the sugars that remain in a wine after fermentation is complete. In some wine styles, such as semi-dry wines, the accurate measurement of the RS concentration is critical for both qualitative and legislative reasons. Brix, measured by a simple refractometer, can give a good estimation of the RS concentration in the must, but during fermentation, the presence of alcohol leads to inaccurate sugar measurements. In order to measure the RS accurately, other more precise techniques are used, most of which are expensive or require professional skills. Therefore, novel approaches for rapid, easy, and practical measurements for estimating the sugar content have been suggested over the years. However, most of these methods do not supply an actual measurement of RS but rather give brix values, and those that measure RS involve special equipment, which is less relevant for small wineries. This study suggests a novel model for predicting and controlling the wine’s residual sugar. The data the model uses is the initial brix of the must before fermentation and its density during fermentation. The model was created by measuring actual residual sugars during the fermentation of natural and synthetic musts, with various degrees of initial brix levels, while simultaneously measuring their densities and correlating the two measurements. Linear regression between the residual sugar of the wine and its density was obtained for all treatments and repetitions (i.e., different values of must initial brix) with R2 values above 0.97. Using the model, one can calculate (before commencing the fermentation) the density values at which the fermentation will reach a particular desired residual sugar value for a specific initial brix level; the model is applicable for the fermentation conditions used in this work, i.e., brix levels of 18–27 °Bx, Saccharomyces cerevisiae strains (fx-33 and fx-10) in common conditions of fermentation regarding temperature and aeration.
]]>Fermentation doi: 10.3390/fermentation10030124
Authors: Ricardo Aleman Ismael Montero-Fernández Jhunior Marcía Selvin Saravia Maldonado Daniel Martín-Vertedor
This review paper addresses vegetable fermentation from a microbiological and technological point of view, with particular emphasis on the potential of lactic acid bacteria to carry out these transformations. This review paper also covers the spectrum of traditional and emerging fermented plant foods. Fermentation with lactic acid bacteria represents an accessible and appropriate strategy to increase the daily consumption of legumes and vegetables. Often, lactic fermentation is carried out spontaneously following protocols firmly rooted in the culture and traditions of different countries worldwide. Fermented plant products are microbiologically safe, nutritious, and have pleasant sensory characteristics, and some of them can be stored for long periods without refrigeration. Controlled fermentation with selected lactic acid bacteria is a promising alternative to guarantee high-quality products from a nutritional and organoleptic point of view and with benefits for the consumer’s health. Recent advances in genomics and molecular microbial ecology predict a bright future for its application in plant fermentation. However, it is necessary to promote molecular approaches to study the microbiota composition, select starters aimed at different legumes and vegetables, generate products with nutritional properties superior to those currently available, and incorporate non-traditional vegetables.
]]>Fermentation doi: 10.3390/fermentation10030123
Authors: Aiping Liu Jie Wu Weixin Zhou Jianlong Li Kaidi Hu Qin Li Ning Zhao Yong Yang Shuliang Liu
Chinese traditional fermented seasonings, essential to the culinary heritage of China, are produced through fermentation, resulting in a diverse range of unique flavors and aromas. The microorganisms involved in fermentation play significant roles in shaping the quality of these traditional fermented seasonings. The production of traditional fermented seasonings is affected by various biological and abiotic factors, presenting challenges concerning product quality and safety. This review investigates the impact of bioaugmentation technology on key Chinese traditional fermented seasonings, such as vinegar, soy sauce, sufu, doubanjiang, dajiang, and douchi. Additionally, the challenges and constraints linked to the implementation of bioaugmentation technology are discussed. The potential of bioaugmentation is highlighted by its ability to shorten the fermentation time, optimize raw material utilization, improve nutritional value, and enhance the quality parameters of these seasonings. This paper demonstrates an interesting convergence of traditional culinary heritage and contemporary technological advancements.
]]>Fermentation doi: 10.3390/fermentation10030122
Authors: Bozena Prusova Josef Licek Michal Kumsta Mojmir Baron Jiri Sochor
This study focuses on the impact of new methods for inhibiting malolactic fermentation in white wines on their analytical and sensory properties. Enological preparations with different mechanisms of effect were tested: fumaric acid, chitosan, Estaan (a preparation based on tannin inhibition), medium-chain fatty acids (MCFAs), sulphur dioxide and a control variant. Malolactic fermentation (MLF) was also performed. The samples underwent analysis through HPLC (high-performance liquid chromatography) to determine the concentrations of malic and lactic acid, as well as biogenic amines. GC (gas chromatography) analysis was used to monitor volatile substances, alongside sensory evaluation. This study demonstrated a significant influence of individual enological preparations on the aromatic profile of the examined wines. The SO2 and MCFA variants exhibited the highest concentrations of volatile substances within the esters group, specifically isoamyl acetate, 1-hexyl acetate and phenylethyl acetate. Conversely, the fumaric acid and Estaan variants displayed the lowest concentrations of these esters. The most notable disparities were observed in acetoin concentration, with the MCFA variant exhibiting the lowest values. Additionally, the chitosan variant showed higher concentrations of putrescine and spermidine compared to the MCFA and fumaric acid variants, which presented the lowest levels.
]]>Fermentation doi: 10.3390/fermentation10030121
Authors: Yingying Liu Yu Zhou Chaohong Zhu Yanglin Meng Jingjing Wang Xinyang Chen Yinchen Hou Aimei Liao Long Pan Jihong Huang
Utilizing wheat embryos as the raw material and employing Aspergillus niger as the fermentation strain, wheat embryo polypeptides were produced through microbial liquid fermentation. The protein concentration post-fermentation served as the response variable, and the preparation process underwent optimization through single-factor testing and a response surface methodology, followed by the assessment of antioxidant activity. The findings revealed that the optimal conditions for wheat embryo peptide preparation via Aspergillus niger fermentation included a fermentation duration of 24 h, an inoculum volume of 4%, an initial pH of 7, and a protein concentration of 21.47 mg/mL. Peptides with different molecular weights were then prepared by dead-end filtration. The results showed that F6 (<3 kDa) had strong scavenging ability against DPPH, ABTS, and ·OH radicals, which provided a basis for the preparation of antioxidant peptides in wheat germ and related research.
]]>Fermentation doi: 10.3390/fermentation10030120
Authors: Denis L. Atroshenko Egor P. Sergeev Diana I. Golovina Anastasia A. Pometun
Recombinant protein expression in Escherichia coli is a fundamental technique in molecular biology and biotechnology. This review provides a comprehensive overview of various additivities to enhance the expression levels of soluble recombinant proteins in E. coli. The discussion encompasses five key aspects. Inducer Optimization: strategies for optimizing the inducer concentration to enhance protein expression. Autoinduction system optimization: the examination of glucose, lactose, and glycerol optimization within autoinduction systems to improve protein production. Osmolytes and osmoprotectants: an analysis of the use of osmolytes and osmoprotectants, such as sorbitol and glycine-betaine, to overcome with ease osmotic stress and enhance protein solubility. Ethanol additives: the impact of ethanol on E. coli physiology and its potential to improve recombinant protein expression. Cofactors and metabolic precursors: insights into the addition of cofactors, such as pyridoxal phosphate, riboflavin, thiamine, and pyridoxine, and the utilization of metabolic precursors to enhance the corresponding protein expression. This review highlights both the successful strategies and challenges in recombinant protein expression and provides insights into potential future research directions. Understanding and optimizing these factors is crucial for the efficient production of recombinant proteins for various applications in biotechnology. Furthermore, based on the analyzed data, we propose a straightforward scheme to optimize the additives in the cultivation medium.
]]>Fermentation doi: 10.3390/fermentation10030119
Authors: Felipe Werle Vogel Nicolas Carlotto Zhongzhong Wang Lydia Garrido Vasiliki Chatzi Raquel Gonzalez Herrero Luis Benavent-Albarracín Javier Martinez Gimenez Loles Carbonell Manuel Porcar
Lignocellulosic biomass is a promising substrate for anaerobic digestion (AD) in renewable energy generation but presents a significant challenge during the hydrolysis stage of conventional AD due to the recalcitrant nature of this biomass substrate. Rumen fluid is often employed as a bioaugmentation seed to enhance hydrolysis in the AD of lignocellulosic substrates due to its richness in hydrolytic bacteria. However, using rumen fluid to enhance AD processes presents substantial hurdles, including the procurement difficulties associated with rumen fluid and ethical concerns. In this study, the fecal microbiota of 10 African ruminant species from a large zoological park (Bioparc) in Valencia, Spain, were studied using 16S rRNA gene amplicon sequencing. In this study, the fecal microbiota of 10 African ruminant species from a large zoological park (Bioparc) in Valencia, Spain, were studied using 16S rRNA gene amplicon sequencing. The investigation revealed potential similarities between the fecal microbiota from the African ruminants’ and cows’ rumen fluids, as suggested by theoretical considerations. Although direct comparative analysis with cow rumen fluid was not performed in this study, the theoretical framework and existing literature hint at potential similarities. According to our results, the Impala, Blesbok, Dikdik and Bongo ruminant species stood out as having the greatest potential to be used in bioaugmentation strategies. Key genera such as Fibrobacter, Methanobrevibacter, and Methanosphaera in Impala samples suggested Impala rumen fluid’s involvement in cellulose breakdown and methane production. Blesbok and Dikdik exhibited a high abundance of Bacillus and Atopostipes, potentially contributing to lignin degradation. The richness of Prevotellaceae and Rikenellaceae in the Bongo fecal samples is probably associated with structural carbohydrate degradation. Taken together, our results shed light on the microbial ecology of the gut contents of a whole set of Bovidae ruminants and contribute to the potential application of gut microbiota in AD.
]]>Fermentation doi: 10.3390/fermentation10030118
Authors: Daniel Asfaw Kitessa Ketema Bacha Yetenayet B. Tola Mary Murimi
Ethiopia has one of the highest levels of malnourished lactating mothers in sub-Saharan Africa. However, traditionally, different communities prepare foods solely for lactating mothers. For example, “Shameta” is one of the cereal-based fermented cultural foods exclusively produced for lactating mothers with the perception that it would support the health, increase the strength, and promote the recovery process of mothers after childbirth. This study investigated the effects of the fermentation time and blending ratio on the nutritional quality of “Shameta”. Three levels of blending ratio of ingredients (maize–barley–fava bean) and three levels of fermentation times were laid down in a completely randomized design (CRD). The study showed that lactic acid bacteria was the dominant group, followed by yeasts. Notably, the ingredient formulation ratio of Maize–barley–fava bean (81:5:5) had the highest LAB dominance with the highest crude fat (13.23 g/100g) content in all fermentation times (8, 10, and 12 days). However, the highest crude protein (16.56 g/100g) and mineral contents were observed in a ratio mix of 66:10:15 fermented for 12 days. The results of this study indicate that the nutritional quality of culturally prepared Shameta can be improved by optimizing the fermentation time and ingredient compositions for fast recovery, increased strength, and improved health of lactating mothers.
]]>Fermentation doi: 10.3390/fermentation10030117
Authors: Thomas Bintsis Photis Papademas
A number of non-thermal preservation strategies have been adopted from the dairy industry to improve cheese quality and safety. The application of lactic acid bacteria cultures that produce bacteriocins has been extensively studied as a means of bio-preservation. However, the application of purified bacteriocins as a bio-protective agent is limited in cheese. The application of protective cultures is another strategy, and the aim of the current review is to provide an overview of the application of commercial and autochthonous adjunct cultures on the bio-protection of cheese; both public health and spoilage aspects are considered.
]]>Fermentation doi: 10.3390/fermentation10030116
Authors: Chan-Hwi Park Hyun Kang Sung-Gyu Lee
In this study, we investigated the enhanced anti-inflammatory activity and the effects on non-alcoholic fatty liver disease (NAFLD) of fermented Fagopyrum tataricum (F. tataricum) Gaertner extract (FFT) through in vitro analysis. We utilized high-performance liquid chromatography (HPLC) to analyze the non-fermented F. tataricum Gaertner extract (NFT) and the marker components, rutin and quercetin in FFT, to confirm changes in composition due to fermentation. The anti-inflammatory activity of NFT and FFT was evaluated using a lipopolysaccharide (LPS)-induced RAW 264.7 cell inflammation model. Simultaneously, the NAFLD improvement effects were measured by evaluating lipid accumulation and the expression of lipid synthesis regulators in free fatty acid (FFA)-induced HepG2 cells. HPLC analysis confirmed an increase in rutin content after the fermentation of F. tataricum Gaertner. Upon treatment with NFT and FFT at a concentration of 400 μg/mL, LPS-induced nitric oxide (NO) production values in RAW 264.7 cells were reduced to 16.12 μM and 2.09 μM, respectively, indicating enhanced significant inhibition (p < 0.05) of NO production through fermentation. FFT demonstrated the significant inhibition (p < 0.05) of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) protein, and inflammatory cytokine mRNA expression through the nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways in LPS-induced RAW 264.7 cells. In FFA-induced HepG2 cells, FFT significant suppressed (p < 0.05) lipid accumulation and the expression of sterol regulatory element binding protein (SREBP)-1c, CCAAT/enhancer binding protein (C/EBP)α proteins, and acetyl-CoA carboxylase (ACC) mRNA. The results of this study suggest the potential utilization of FFT as a material for improving NAFLD.
]]>Fermentation doi: 10.3390/fermentation10030115
Authors: Zhuoyu Wang Andrej Svyantek Zachariah Miller Aude A. Watrelot
This research is the first study of McIntosh apple cider fermentation using different must treatments. The must materials included standard pressed juice, the common cider fermentation material, mash, direct from the apple shredder both with and without pectinase additions, and finally, pomace. These four treatments caused multiple differences from the standard hard ciders from juice, starting with the apple must characteristics, following through the yeast fermentation processes, and carried into the final ciders. Initial apple musts had different sugar content, pH, acids, total phenolics, and antioxidant activities. Although juice contained more total phenolics and had more antioxidant capabilities, it contained lower levels of yeast assimilable nitrogen. The sugar consumption dynamic changes had a differential dynamic trend but did not alter the capacity for complete apple cider fermentation. From the fermentation color dynamic changes, it indicated that must materials would have effects on color-changing amplitudes. Juice treatment had the largest changes from the must. Pomace and mash with pectinase had fewer color changes in multiple color values (L*, a*, b*). The mono phenolics in the final cider indicated that pomace ferments contained the least hydroxycinnamates but a similar amount of total flavanols as juice-fermented ciders. Cider from the juice contained the least flavonols, whereas the mash, both with and without pectinase treatments, had the largest amount of flavonols. This work will provide some applicable information for apple cider fermentation from the apple wastes in the cider industry.
]]>Fermentation doi: 10.3390/fermentation10020114
Authors: Joel O. Alabi Peter A. Dele Deborah O. Okedoyin Michael Wuaku Chika C. Anotaenwere Oludotun O. Adelusi DeAndrea Gray Kelechi A. Ike Olatunde A. Oderinwale Kiran Subedi Uchenna Y. Anele
This study investigated the combined impact of essential oil blends (EOBs) and fumaric acid (FA) on ruminal fermentation in dairy cows using the rumen simulation technique (RUSITEC) system. Three rumen-cannulated, non-lactating Holstein Friesian cows served as inoculum donors. The substrate, a total mixed ration (TMR), comprised corn silage, alfalfa hay, and a concentrate mix in a 3:1:1 ratio. The four treatments evaluated were Control (TMR without additives), EFA1 (TMR + EOB1 + FA), EFA2 (TMR + EOB2 + FA), and EFA3 (TMR + EOB3 + FA). Sixteen fermentation chambers were randomly assigned to the treatments, each with four replicates, following a completely randomized design during a 9-day experimental period. EOBs and FA were added at 10 µL/g feed and 3% of TMR, respectively. After a 4-day adaptation, samples were collected for 5 days. Results revealed that EFA1 significantly reduced (p = 0.0351) CH4 emissions by 60.2% without negatively impacting dry matter disappearance, fiber fraction digestibility, pH, or gas volume. All EFAs increased (p < 0.001) the propionate molar proportion and decreased (p < 0.001) the acetate-to-propionate ratio. EFA2 decreased (p < 0.05) the acetate proportion by 3.3% compared to the control. In conclusion, EFA1 is recommended as an effective nutritional intervention to mitigate CH4 emissions and optimize ruminal fermentation in dairy cows.
]]>Fermentation doi: 10.3390/fermentation10020113
Authors: Rojas-Flores Segundo Magaly De La Cruz-Noriega Luis Cabanillas-Chirinos Nélida Otiniano Nancy Soto-Deza Walter Rojas-Villacorta Mayra De La Cruz-Cerquin
Currently, industry in all its forms is vital for the human population because it provides the services and goods necessary to live. However, this process also pollutes soils and rivers. This research provides an environmentally friendly solution for the generation of electrical energy and the bioremediation of heavy metals such as arsenic, iron, and copper present in river waters used to irrigate farmers’ crops. This research used single-chamber microbial fuel cells with activated carbon and zinc electrodes as anodes and cathodes, respectively, and farmers’ irrigation water contaminated with mining waste as substrate. Pseudomonas stutzeri was used as a biocatalyst due to its ability to proliferate at temperatures between 4 and 44 °C—at which the waters that feed irrigated rivers pass on their way to the sea—managing to generate peaks of electric current and voltage of 4.35 mA and 0.91 V on the sixth day, which operated with an electrical conductivity of 222 mS/cm and a pH of 6.74. Likewise, the parameters of nitrogen, total organic carbon, carbon lost on the ignition, dissolved organic carbon, and chemical oxygen demand were reduced by 51.19%, 79.92%, 64.95%, 79.89%, 79.93%, and 86.46%. At the same time, iron, copper, and arsenic values decreased by 84.625, 14.533, and 90.831%, respectively. The internal resistance values shown were 26.355 ± 4.528 Ω with a power density of 422.054 mW/cm2 with a current density of 5.766 A/cm2. This research gives society, governments, and private companies an economical and easily scalable prototype capable of simultaneously generating electrical energy and removing heavy metals.
]]>Fermentation doi: 10.3390/fermentation10020112
Authors: Xun Liu Weijie Yang Hongyi Gu Ayaz Ali Bughio Jun Liu
2,3,5-trimethylpyrazine (TMP), as a volatile heterocyclic nitrogen compound, has a wide range of applications. To explore an efficient and environmentally friendly way to produce TMP, Bacillus strains were isolated from Daqu using traditional separation and purification methods. The fermentation products were detected by gas chromatography–mass spectrometry (GC-MS), and the species relationship of strains was analyzed by morphological and phylogenetic tree construction. Single factors were selected to optimize the fermentation process of TMP production, and a Box–Behnken design was used for response surface testing. The LC-6 strain isolated from Daqu was Bacillus amyloliquefaciens, and its fermentation products contained TMP, with a relatively high value of 0.071 ± 0.011 mg/g, indicating that the LC-6 strain was a potentially valuable TMP-producing bacterium. The results of single-factor testing showed that temperature, bottle capacity, and water addition significantly affected TMP production. Box–Behnken design and response surface analysis revealed that the order of influence on TMP yield was as follows: water addition > temperature > bottle capacity. Response surface optimization results showed that the optimal parameters for wheat medium fermentation were temperature 37 °C, bottle capacity 100 g/250 mL, and water addition 39 mL. Under these fermentation conditions, the average production of TMP was 0.446 ± 0.052 mg/g, which was 0.375 mg/g higher than that obtained before optimization. Compared with the previous period, the production of TMP indeed increased, providing a basis for further research on the solid-state fermentation process of TMP synthesis.
]]>Fermentation doi: 10.3390/fermentation10020111
Authors: Yiling Xiong Chenglin Zhu Baozhu Wu Tianyang Wang Lian Yang Ju Guan Yuwen Yi Jing Deng Huachang Wu
Salt is a key ingredient that can both enhance the taste and extend the shelf life of fermented vegetables. However, it is important to note that excessive salt levels can have adverse effects on consumer health. This study aimed to investigate the impact of various salt additions (2%, 4%, 6%, 8%, and 10% wt/wt) on the flavor profile of fermented ciba pepper, a traditional Chinese fermented chili sauce, using gas chromatography–ion mobility spectrometry (GC-IMS) in combination with an electronic nose (E-nose). Fermented ciba pepper samples were prepared with different salt additions: 2% (LJA), 4% (LJB), 6% (LJC), 8% (LJD), and 10% (LJE) (wt/wt). The physicochemical and sensory properties of the fermented ciba pepper samples were evaluated. Sensory evaluation indicated that LJC and LJD received higher scores compared to the other groups. The total acid and amino acid nitrogen contents displayed contrasting trends with the salt additions (p < 0.05). The E-nose analysis successfully differentiated the flavor profiles of the ciba pepper samples fermented with varying salt additions. Additionally, the GC-IMS analysis identified a total of 72 volatile compounds, including 14 alcohols, 21 esters, nine aldehydes, four acids, eight ketones, three terpenes, and eight other substances. Notably, the ciba pepper samples with lower salt additions exhibited higher levels of alcohols, aldehydes, and esters. In conclusion, the addition of salt during the fermentation process significantly influenced the formation of flavor compounds in ciba pepper. This study provides valuable insights into ciba pepper fermentation with different salt additions and offers prospects for the development of low-salt fermented ciba pepper products.
]]>Fermentation doi: 10.3390/fermentation10020110
Authors: Jenny Nathalia Álvarez-Torres Jacinto Efrén Ramírez-Bribiesca Yuridia Bautista-Martínez María Magdalena Crosby-Galván Lorenzo Danilo Granados-Rivera Mónica Ramírez-Mella Alexis Ruiz-González
Few studies have evaluated the impact of a lipid-rich diet with palmitic acid (PA) in ruminal fermentation. The objective was to evaluate the in vitro bath culture of the protected PA on the ruminal fermentative variables. Four diets were used: (a) without protected PA (nPA) and (b) inclusion of protected PA at three levels: PA3 = 3%, PA6 = 6%, and PA9 = 9% dry matter (DM). The maximum gas production occurred without including protected PA and the low gas production given with the inclusion of protected PA9 (p ≤ 0.05). Meanwhile, the inclusion with 3 and 6% of protected PA showed a higher level of gas production kinetics than the other treatments (p ≤ 0.05). DM and organic matter degradation after 72 h of incubation linearly decreased (p ≤ 0.05) with a high level of protected PA. The level of C16:0 in the protected AP increased with the higher level of supplemented AP (p ≤ 0.05). The best efficiency in propionic acid, decrease in methane, and increase in biohydrogenation (79%) occurred with the inclusion of protected PA3 (p ≤ 0.05). In conclusion, supplements with protected PA at 3 and 6% increased PA availability. The results indicate good benefits of protected PA on fermentative variables, and these doses seem ideal for future research in lactating goats.
]]>Fermentation doi: 10.3390/fermentation10020109
Authors: Jieyi Peng Shuo Zhao Ying Li Zhen Wang Li Chen
Microbial electrochemical systems have shown great value as a means of enhancing the efficiency of fermentation reactions, but at present, there is no reliable means to balance the extracellular electron supply and corresponding intracellular demands in these systems. The current work describes the unique use of an oxidation–reduction-potential (ORP)-level-controlled microbial electrolysis cell (MEC) system to successfully balance the extracellular electron supply and succinic acid fermentation via A. succinogenes (130Z). The ORP-controlled MEC system with neutral red (NR) yielded a significant increase in succinic acid production (17.21%). The utilization of NR in this MEC system improved the ORP regulatory sensitivity. The optimal approach to the ORP level control was the use of a −400 mV high-voltage electric pulse-based strategy, which increased the yield of succinic acid by 13.08% compared to the control group, and reduced the energy consumption to 52.29% compared to the potentiostatic method. When compared to the −1 V constant potential MEC system, the high-voltage electric pulse-based ORP strategy for the MEC system control provided sufficient electrons to this system while using less electricity (11.96%) and producing 12.48% (74.43 g/L) more succinic acid during fed-batch fermentation. The electronic utilization efficiency of the ORP-controlled MEC system was 192.02%, which was 15.19 times that of the potentiostatic system. The electronic utilization efficiency is significantly increased in the ORP-controlled MEC system. Succinic acid production is ensured by a high-voltage electric pulse-based method, while the influence on cell growth and power consumption are minimized. Fed-batch fermentation with the high-voltage electric pulse-based ORP strategy for MEC system control is noted to be ideal to achieve a further increase in succinic acid concentration and electronic utilization efficiency.
]]>Fermentation doi: 10.3390/fermentation10020108
Authors: Rajan Dhakal André Luis Alves Neves Rumakanta Sapkota Prabhat Khanal Hanne Helene Hansen
Background: This study aimed to investigate the impact of in vitro rumen fermentation (IVRF) on the microbiome structure and composition of rumen fluid before and after fermentation assays. Methods and Results: Six separate fermentation batches were run for 48 h using maize silage as the basal feed. Rumen fluid samples were analyzed before (RF; only rumen fluid inoculant) and after 48 h fermentation assay (MS; maize silage as the substrate) and further processed for microbiome analysis using amplicon sequencing targeting the V4 region of the bacterial 16S rRNA gene. Bacterial alpha diversity revealed that the Shannon index and observed index were similar between MS and RF fluid. The core microbiome was detected in 88.6% of the amplicon sequence variants in MS and RF. Taxonomic analysis at the phylum level showed similar abundances of Bacteroidetes, Proteobacteria, Firmicutes, Verrucomicrobiota, Spirochaetota, Patescibacteria, and Campilobacterota in MS and RF. The Bray–Curtis distance matrix showed similar bacterial community structure among MS and RF samples. Conclusion: Our results indicated that the in vitro procedure did not affect the bacterial community structure compared to the original rumen fluid inoculum. It should be noted that assessing the microbiome at a single endpoint (i.e., 48 h) may not provide a comprehensive understanding of the microbiome profile dynamics. However, the findings of this study provide a basis for future microbiome-based in vitro fermentation tests and confirm that the technique allows a high degree of species diversity that approximates the rumen function in vivo.
]]>Fermentation doi: 10.3390/fermentation10020107
Authors: Małgorzata Kasprowicz-Potocka Anita Zaworska-Zakrzewska Dagmara Łodyga Damian Józefiak
Enzymatic solid-state fermentation can improve the nutritional quality of feed materials. The current study aimed to determine the effect of the solid-state fermentation of rapeseed meal (RSM) with carbohydrase/s and phytases in various combinations. RSM was fermented for 24 h at 25 °C with eight commercial preparations and mixtures thereof to prepare eleven products (PHYL—liquid-6-phytase; RON NP—6-phytase; RON HI—6-phytase; RON R—α-amylase; RON WX—β-xylanase; RON VP—β-glucanase; RON A—α-amylase, β-glucanase; RON M—xylanase, β-glucanase; RON NP+M; RON NP+A; RON NP+M+R). Afterward, the enzymes were deactivated at 70 °C within 15 min, and the biomass was dried for 24 h at 55 °C. Carbohydrase and/or phytase additives did not positively affect crude or true protein content or reduce crude fiber (p > 0.05). Among the products after fermentation, a significant reduction in the content of the raffinose family oligosaccharides, glucosinolates, and phytate was found. In the presence of phytase, the phytate reduction was more significant (p < 0.01) than that in the presence of carbohydrases only. The addition of carbohydrases together with phytases did not improve the results in comparison with phytases alone (p > 0.05). The most valuable effect was found for liquid-6-phytase (PHYL).
]]>Fermentation doi: 10.3390/fermentation10020106
Authors: Hissashi Iwamoto Carlos Ricardo Soccol Denisse Tatiana Molina-Aulestia Juliana Cardoso Gilberto Vinícius de Melo Pereira Luciana Porto de Souza Vandenberghe Maria Clara Manzoki Ranga Rao Ambati Gokare Aswathanarayana Ravishankar Júlio Cesar de Carvalho
Lutein, a yellow xanthophyll carotenoid, is increasingly recognized for its nutraceutical benefits, particularly in protecting the retina’s macula from age-related degeneration. Microalgae are a promising source of lutein, which can be a primary product or a coproduct in biorefineries. Certain microalgae exhibit lutein levels (up to 1.7%) surpassing those of common dietary sources like kale, spinach, and egg yolk (approximately 0.7–0.9%). Predominantly associated with photosystem II’s light-harvesting complex, lutein is crucial in photosynthesis and cellular defense. However, being quantitatively minor among cellular constituents, lutein necessitates specialized processing for efficient extraction. Although ubiquitous in microalgae, it is not as easily inducible as β-carotene and astaxanthin in Dunaliella salina and Haematococcus pluvialis, respectively. Currently, microalgal lutein production predominantly occurs at the bench scale, presenting challenges in scaling up. Factors like culture medium significantly influence biomass and lutein yields in industrial production, while downstream processing requires cost-effective, food-grade solvent extraction techniques. This review delves into contemporary methods and innovative progress in microalgal lutein production, emphasizing industrial-scale processes from biomass cultivation to final product formulation. A conceptual industrial process proposed in this review shows that two 10 m3 photobioreactors could produce 108 kg dry mass for Chlorella minutissima, which can be processed into approximately 616 g of lutein extract, or over 6000 capsules of finished nutraceutical daily. Despite lutein production via microalgae being in nascent stages at large scales, existing research provides a solid foundation for well-informed scale-up endeavors.
]]>Fermentation doi: 10.3390/fermentation10020105
Authors: Paola Hernández-Carranza Bricia A. Mendoza-Gutiérrez Karen H. Estévez-Sánchez Carolina Ramírez-López Silvia del C. Beristain-Bauza Sandra V. Avila-Reyes Irving I. Ruíz-López Carlos E. Ochoa-Velasco
This study aimed to develop bioactive bi-layer edible films based on starch (primary layer) and LAB-fermented whey and/or mango pulp powder solutions (secondary layer). Bioactive bi-layer edible films were evaluated for their physical properties, mechanical properties, antioxidant capacity, and Lactobacillus rhamnosus availability for 28 days (4 and 20 °C). Selected bioactive bi-layer edible film was applied to sushi to evaluate its sensory acceptance. The results indicated that bi-layer edible films based on LAB-fermented whey/mango solutions presented a higher quantity of phenolic compounds (95.87–107.67 mg GAE/100 g) and higher antioxidant capacity (74.84–77.64%). In addition, the higher viability (106–107 CFU/g) of L. rhamnosus after edible film production was obtained in those formulated with whey. After the storage period, the antioxidant capacity of all edible films was significantly affected by the storage time, while edible films containing whey in their formulation and stored at 4 °C had a L. rhamnosus count higher than 6 log cycles, which is the minimum required threshold to exert its beneficial effects in humans. The sushi covered with the selected bi-layer edible film was well accepted by the consumers, showing acceptance values between “I like it” and “I like it much”. Therefore, the developed bi-layer edible films can serve as an alternative for adding health-promoting compounds to sushi with an adequate sensory acceptance of the consumers.
]]>Fermentation doi: 10.3390/fermentation10020104
Authors: Snežana Škaljac Marija Jokanović Tatjana Peulić Jelena Vranešević Brankica Kartalović Vladimir Tomović Predrag Ikonić Branislav Šojić
This study examined the safety of meat products from north Serbia (Vojvodina), smoked in traditional conditions, from a PAH point of view, and assessed the possibility of their reduction in these types of products. Samples of dry cured meat products, bacons and dry fermented sausages smoked in six different chambers on the territory of Vojvodina were examined. The contents of 16 polycyclic aromatic hydrocarbons, from the United States Environmental Protection Agency list (16 US-EPA PAHs), and sensory quality of meat products were determined. The total content of 16 US-EPA PAHs in dry cured meat products was in the range from 99.73 μg/kg to 412.76 μg/kg; in bacons it was in the range from 36.43 μg/kg to 188.86 μg/kg; and in dry fermented sausages in the range from 47.23 μg/kg to 270.60 μg/kg. The lowest contents of 16 US-EPA PAHs compounds were determined in meat products smoked in traditional conditions during 3–5 days (3–4 h per day) at a distance of 2.5 m between the fire and products. Generally, it can be concluded that shortening of smoking process is justified, because products of good sensory quality and with decreased content of PAHs compounds were obtained. Benzo[a]pyrene, whose maximum allowed content in smoked meat products is 2 μg/kg, was below the limit of detection in all examined traditional meat products from Vojvodina. Also, contents of PAH4, sum of benz[a]anthracene, chrysene, benzo[a]pyrene and benzo[b]fluoranthene, were in the range from ND to 2.22 μg/kg, still greatly lower than the set maximum value. These results indicated the safety of dry cured meat products, bacons and dry fermented sausages from the territory of north Serbia (Vojvodina), as defined by EU Regulation 2023/915 criteria for PAHs contents.
]]>Fermentation doi: 10.3390/fermentation10020103
Authors: Shuyue Zhang Zhe Feng Qingming Zeng Junhao Zeng Huijing Liu Pan Deng Shangyu Li Nan Li Junqing Wang
This study addresses the production enhancement of pullulan, an extracellular polysaccharide with various applications. Pullulan is primarily produced by Aureobasidium pullulans (A. pullulans), and genetic modification is commonly used to increase its yield. However, there is a need for a more efficient and safer method. To achieve this, we designed a high-throughput screening system utilizing a unique fluorescent protein specific to pullulan. Ultraviolet (UV) mutagenesis was applied to create a pool of mutant strains, and flow cytometry allowed for single-cell screening. Our approach yielded strain M1-B3, which exhibited a substantial increase in pullulan production from 26.5 g/L to 76.88 g/L. Additionally, the molecular weight of the produced pullulan significantly increased, expanding its potential commercial application. This study demonstrates an efficient and safe method to enhance pullulan production in A. pullulans. The UV mutagenesis and flow cytometry based on screening not only increased yield but also improved pullulan’s molecular weight. The adaptability of this method to other polysaccharides and its potential for genomic analysis and broader applications make it a valuable tool in bioproduction.
]]>Fermentation doi: 10.3390/fermentation10020102
Authors: Anne Oppelt Anton Rückel Markus Rupp Dirk Weuster-Botz
Providing simultaneously autotrophic and heterotrophic carbon sources is a promising strategy to overcome the limits of autotrophic syngas fermentations. D-xylose and L-arabinose are particularly interesting as they can be obtained by the hydrolysis of lignocellulosic biomass. The individual conversion of varying initial concentrations of these pentoses and D-fructose as reference was studied with C. autoethanogenum in fully controlled stirred-tank reactors with a continuous syngas supply. All mixotrophic batch processes showed increased biomass and product formation compared to an autotrophic reference process. Simultaneous CO and D-xylose or L-arabinose conversion was observed in contrast to D-fructose. In the mixotrophic batch processes with L-arabinose or D-xylose, the simultaneous CO and sugar conversion resulted in high final alcohol-to-acid ratios of up to 58 g g−1. L-arabinose was superior as a mixotrophic carbon source because biomass and alcohol concentrations (ethanol and 2,3-butanediol) were highest, and significant amounts of meso-2,3-butanediol (>1 g L−1) in addition to D-2,3-butanediol (>2 g L−1) were solely produced with L-arabinose. Furthermore, C. autoethanogenum could not produce meso-2,3 butanediol under purely heterotrophic conditions. The mixotrophic production of meso-2,3-butanediol from L-arabinose and syngas, both available from residual lignocellulosic biomass, is very promising for use as a monomer for bio-based polyurethanes or as an antiseptic agent.
]]>Fermentation doi: 10.3390/fermentation10020101
Authors: María Carla Groff Sandra Edith Noriega Rocío Mariel Gil Nadia Pantano Gustavo Scaglia
Lactic acid is widely used in the food industry. It can be produced via chemical synthesis or biotechnological pathways by using renewable resources as substrates. The main challenge of sustainable production lies in reaching productivities and yields that allow for their industrial production. In this case, the application of process engineering becomes a crucial tool to improve the performance of bioprocesses. In this work, we performed the solid-state fermentation of grape stalk using Rhizopus oryzae NCIM 1299 to obtain lactic acid, employing three different temperatures (22, 35, and 40 °C) and a relative humidity of 50%. The Logistic and First-Order Plus Dead Time models were adjusted for fungal biomass growth, and the Luedeking and Piret with Delay Time model was used for lactic acid production, obtaining higher R2 values in all cases. At 40 °C, it was observed that Rhizopus oryzae grew in pellet form, resulting in an increase in lactic acid productivity. In this context, the effect of temperature on the kinetic parameters was evaluated with a polynomial correlation. Finally, using this correlation, a smooth and continuous optimal temperature profile was obtained by a dynamic optimization method, improving the final lactic acid concentration by 53%.
]]>Fermentation doi: 10.3390/fermentation10020100
Authors: Islam Sayah Claudio Gervasi Sami Achour Teresa Gervasi
Bacterial cellulose (BC) is a pure exocellular polysaccharide produced by micro-organisms. It has several properties in comparison with plant-derived cellulose that make it perfectly suitable for many applications, ranging from the food industry to the biomedical area. Different production methods and modification or functionalization procedures have been investigated in response to the many possible attractive applications of BC. This review overviews the different fermentation techniques and functionalization methods together with the main possible biotechnological applications of BC for food industry and biomedical purposes.
]]>Fermentation doi: 10.3390/fermentation10020099
Authors: Bingkun Li Yiheng Zheng Shida Zhao Yaohan Zhang Ding Li
E2-Spy (abbreviated as ES) plays a vital role as a component in the Bacterial-Like Particles (BLPs) vaccine against classical swine fever virus (CSFV). This vaccine demonstrates remarkable immunoprotection, highlighting the importance of augmenting ES production in the development of CSFV subunit vaccines. In this study, a Pichia pastoris strain capable of high-yield secretory production of ES was developed through signal peptide engineering, gene dosage optimization and co-expression of molecular chaperones. Initially, a hybrid signal peptide cSP3 was engineered, leading to a 3.38-fold increase in ES production when compared to the control strain 1-α-ES. Subsequently, cSP3 was evaluated for its expression efficiency alongside different commonly used signal peptides under multicopy conditions. SDS-PAGE analysis revealed that 2-αd14-ES exhibited the highest ES production, displaying a 4.38-fold increase in comparison to 1-α-ES. Afterwards, SSA1, YDJ1, BIP, LHS1, and their combinations were integrated into 2-αd14-ES, resulting in a 1.92-fold rise in ES production compared to 2-αd14-ES (equivalent to a 6.18-fold increase compared to 1-α-ES). The final yield of ES was evaluated as 168.3 mg/L through comparison with serially diluted BSA protein bands.
]]>Fermentation doi: 10.3390/fermentation10020098
Authors: Takahisa Tajima Shiina Kawaguchi Tomoka Matsutani Akiko Hida Junichi Kato
As methane fermentation is inhibited by ammonia derived from organic waste, anaerobic microbial communities tolerant to enriched wastewater with high concentrations of ammonia and salt must be obtained for methane fermentation. Therefore, acclimation cultures were prepared in bottles for 60–80 weeks with artificial wastewater medium added every 2 weeks, using three types of sludge from wastewater treatment plants in food factories. These cultures were maintained without substantially decreasing methanogenesis and gradually increasing NH4-N and salt concentrations to 5 and 34 g/L, respectively, via the accumulation of ammonia and salt through anaerobic digestion and direct addition. The culture did not show the severe inhibition of methanogenesis or the accumulation of volatile fatty acids (VFAs) such as acetic and propionic acids. The analysis of bacterial consortia in the acclimated sludge based on the 16S rRNA sequence showed that hydrogenotrophic methanogenic bacteria of the genus Methanoculleus were dominant among archaea, whereas bacteria from the orders Clostridiales and Bacteroidales were dominant among eubacteria. Further, VFA-assimilating bacteria, including synthetic acetate-oxidizing bacteria coupled with hydrogenotrophic Methanoculleus to convert methane from acetate, were present to prevent the excessive accumulation of VFAs in the acclimation culture. The proposed acclimation process can enhance the anaerobic digestion of wastewater for methane production.
]]>Fermentation doi: 10.3390/fermentation10020097
Authors: Liliana Londoño-Hernández María de Jesús García-Gómez Sergio Huerta-Ochoa Anna María Polanía-Rivera Cristóbal Noé Aguilar Lilia Arely Prado-Barragán
Proteases are important enzymes because of their extended uses in several industries, such as food, beverages, pharmacy, detergents, and many others. Aspergillus is one of the most used fungi strains for enzyme production by solid-state fermentation (SSF). Disponibility of the carbon source is a key factor for protease production. In addition, the selection of solid support has great importance, as it must provide suitable airflow through the packed bed and nutrient diffusion inside the fermentable mass. Six Aspergillus strains and two inert supports (Agrolite (AL) and Polyurethane (PUF)) were tested for protease production from fish flour (FF) at different glucose concentrations (0, 5, 10, 15%) by SSF. The FF/PUF mixture at 70/30 (w/w) ratio, with 75.39% moisture, and a critical moisture point of 0.11 gH2O/g, presented a texture that allowed heat and mass transfer and provided enough moisture to make free water available as required for microorganism growth during the fermentation process. Aspergillus oryzae 2095 produced higher amounts of neutral and alkaline proteases with the addition of 5% glucose to the growth medium. Kinetics studies reveal that protease production is partially associated with growth. The extracts obtained can be used in different industries, and especially to prepare fish high-value by-product hydrolysates.
]]>Fermentation doi: 10.3390/fermentation10020096
Authors: Liangcheng Yang Tuba Yasmin Lubna Michael A. Moklak Barsanti Gautam Nicholas J. Heller Robert L. Rhykerd David E. Kopsell John C. Sedbrook
Pennycress (Thlaspi arvense L.) is an annual cover crop known for its exceptional cold tolerance and high oil and protein yields. Pennycress can be integrated into a corn–soybean rotation in the U.S. However, the utilization of pennycress biomass remains largely unexplored, including assessing compositional changes through its growth and organic matter digestibility. This study harvested pennycress at three growth stages, characterized the biomass for anaerobic digestion (AD), and tested the effects of concurrent alkali pretreatment and ensiling on the biomass methane yield. Results showed that the biomass harvested when the plants were undergoing senescence (“third-harvest”) had higher contents of acid detergent fiber, neutral detergent fiber, and lignin, while the biomass harvested when 80–90% of the pods were fully-sized (“second-harvest”) had the highest protein content. The AD experiments showed that the first-harvest biomass (90% of flowers opened) failed to produce biogas due to a drop in the pH and alkalinity, the second-harvest biomass was inhibited for methane production (45.74 ± 0.20 L/kg-VS), and the third-harvest biomass had a methane yield of 171.80 ± 4.82 L/kg-VS. After the alkali pretreatment and ensiling, a methane yield of 270.4 ± 3.10 L/kg-VS was obtained from the second-harvest biomass, representing a significant 4.5-fold increase (adjusted for the organic matter loss) relative to the untreated second-harvest biomass.
]]>Fermentation doi: 10.3390/fermentation10020095
Authors: Peng Wu Ni Wang
As we conclude our exploration of the Special Issue, “Bioactive Compounds in Grain Fermentation”, it is essential to revisit the origins of this initiative, providing a clear understanding of its objectives [...]
]]>Fermentation doi: 10.3390/fermentation10020094
Authors: Xirui Zhang Yao Liu Zizhen Zuo Chenxi Wang Zhongli Peng Jincheng Zhong Haibo Wang
This study aims to investigate the effect of methionine analogue 2-hydroxy-4-methylthiobutanoic acid isopropyl ester (HMBi) on the rumen microbial community, microbial carbohydrate-active enzymes (CAZy), and protein metabolism pathways in yak. Twenty-four male Maiwa yaks (252.79 ± 15.95 kg) were selected and randomly divided into groups that received the basal diet alone, or a diet supplemented with different amounts of HMBi (5 g, 10 g or 15 g). At the phylum level, the group receiving 5 g of HMBi showed a considerably higher relative abundance of Lentisphaerae than the other treatment groups (p < 0.05). The relative abundance of Actinobacteria decreased linearly with the increase in HMBi supplemental levels (p < 0.05). The relative abundance of Prevotella increased linearly with the increasing level of HMBi supplementation (p < 0.05). The relative abundance of Butyrivibrio linearly decreased (p < 0.05), and the relative abundance of Alistipes tended to linearly decrease (p = 0.084). The addition of HMBi had linear or quadratic effects on the relative abundance of CAZy enzymes and functional proteins in the rumen of yak (p < 0.05). Conclusively, these results indicated that feeding yaks a diet supplemented with HMBi is an excellent strategy to enhance carbohydrate breakdown, and improve rumen microbial structure and function.
]]>Fermentation doi: 10.3390/fermentation10020093
Authors: Milica Crnoglavac Popović Marija Stanišić Radivoje Prodanović
Oxidoreductase (OXR) enzymes are in high demand for biocatalytic applications in the food industry and cosmetics (glucose oxidase (GOx) and cellobiose dehydrogenase (CDH)), bioremediations (horseradish peroxidase (HRP) and laccase (LAC)), and medicine for biosensors and miniature biofuel cells (GOx, CDH, LAC, and HRP). They can be used in a soluble form and/or within the yeast cell walls expressed as chimeras on the surface of yeast cells (YSD), such as P. pastoris and S. cerevisiae. However, most of the current studies suffer from either low yield for soluble enzyme expression or low enzyme activity when expressed as chimeric proteins using YSD. This is always the case in studies dealing with the heterologous expression of oxidoreductase enzymes, since there is a requirement not only for multiple OXR gene integrations into the yeast genome (super transformations), and codon optimization, but also very careful design of fermentation media composition and fermentation conditions during expression due to the need for transition metals (copper and iron) and metabolic precursors of FAD and heme. Therefore, scientists are still trying to find the optimal formula using the above-mentioned approaches; most recently, researcher started using protein engineering and directed evolution to increase in the yield of recombinant enzyme production. In this review article, we will cover all the current state-of-the-art technologies and most recent advances in the field that yielded a high expression level for some of these enzymes in specially designed expression/fermentation systems. We will also tackle and discuss new possibilities for further increases in fermentation yield using cutting-edge technologies such as directed evolution, protein and strain engineering, high-throughput screening methods based on in vitro compartmentalization, flow cytometry, and microfluidics.
]]>Fermentation doi: 10.3390/fermentation10020092
Authors: Jiangbo An Lin Sun Mingjian Liu Rui Dai Qiang Si Gentu Ge Zhijun Wang Yushan Jia
Nitrites are universally acknowledged natural toxic substances that frequently lead to poisoning in humans and animals. During fermentation, certain microorganisms utilize a portion of the nitrogen element and reduce nitrates to nitrites through specific metabolic pathways. In this study, a highly effective lactic acid bacterial strain, Lactiplantibacillus plantarum A50, was isolated and screened from alfalfa silage for its remarkable ability to degrade nitrites. L. plantarum A50 exhibits exceptional nitrite removal capacity, with a degradation rate of 99.06% within 24 h. Furthermore, L. plantarum A50 demonstrates normal growth under pH values ranging from 4 to 9 and salt concentrations of 5%, displaying excellent tolerance to acidity, alkalinity, and salinity. Additionally, it undergoes fermentation using various carbon sources. Within the first 6–12 h of culture, L. plantarum A50 primarily achieves nitrite degradation through non-acidic processes, resulting in a degradation rate of 82.67% by the 12th hour. Moreover, the metabolites produced by L. plantarum A50 exhibit a synergistic interaction with acidity, leading to a nitrite degradation rate of 98.48% within 24 h. Notably, both L. plantarum A50 and MRS broth were found to degrade nitrites. Consequently, a non-targeted metabolomic analysis using LC-MS was conducted to identify 342 significantly different metabolites between L. plantarum A50 and MRS broth. Among these, lipids and lipid-like molecules, organic acids and derivatives, organic oxygen compounds, and organoheterocyclic compounds emerged as the main constituents. Lipids and lipid-like molecules, derivatives of glucose and galactose, amino acids and their derivatives, as well as organoheterocyclic compounds, are likely to play a role in nitrite elimination. Through the enrichment analysis of differential metabolic pathways using KEGG, nine distinct pathways were identified. These pathways provide essential nutrients, maintain cellular structure and function, participate in substance transport, regulate metabolic activities, and enhance resistance against pathogenic microorganisms in L. plantarum A50.
]]>Fermentation doi: 10.3390/fermentation10020091
Authors: Mekala Venkatachalam
There has been a continuous increase in consumer awareness regarding the availability of natural, sustainable, biodegradable options in all sectors, including food, cosmetics, pharmaceuticals, textiles, painting, printing inks, etc [...]
]]>Fermentation doi: 10.3390/fermentation10020090
Authors: Tianyu Lu Bei Song Jinsong Yang Haisheng Tan Huahua Qiao Wenbo Zhi Rong Chen Zhanwu Sheng
In order to promote the consumption and application of cassava in the food industry, the cassava–acerola cherry juice beverage was developed using lactic acid bacteria fermentation, which improved the flavor attraction and nutritional value, increased the added value of cassava and acerola cherry. The study investigated the effects of both pure and mixed fermentation using Lactobacillus plantarum (L. plantarum) HNC7 on the chemical compounds and antioxidant activities in cassava–acerola cherry juice. Following 72 h of fermentation, the fruit juice showed increased acidity, a decrease in pH, and higher consumption of soluble solids, and a significant rise in volatile substance content and antioxidant activity (p < 0.05). Notably, the HNC7-YLC92 binary combination demonstrated the most effective fermentation, resulting in a product with uniform color, moderate sourness and sweetness, and a delicate and smooth taste. Overall, the HNC7-YLC92 binary combination, due to its beneficial biological properties, shows great potential as the optimal strain for fermenting this juice. This provides a reference for selecting industrial fermentation conditions and strains, aiming to develop new value-added cassava products and increase their consumption.
]]>Fermentation doi: 10.3390/fermentation10020089
Authors: Kanako Matsunaga Yasuhiko Komatsu
Since ancient times, the placenta has been used to produce cosmetic and health food products, whereas fermentation is a technology that has been used to produce foods and cosmetics. For application in cosmetics, traditional placental extracts produced solely by proteolysis have not had enough moisturizing properties or the ability to stimulate the proliferation of epidermal keratinocytes. We combined these two traditional approaches to produce raw materials without such drawbacks that are suitable for cosmetic applications. Using a unique lactic acid bacterial strain, Enterococcus faecalis PR31, to directly ferment and digest both porcine and equine placentas, we produced the following liquid products: placenta ferment filtrates. The ferment filtrates stimulated the proliferation of not only normal human dermal fibroblasts but also epidermal keratinocytes. The ferments had higher equilibrium water content properties than traditional placental extracts, and the ferment derived from the porcine placenta maintained high stratum corneum water content levels for up to 6 h after its application on the skin. Metabolome analysis revealed various molecules that were increased by fermentation, among which lactic acid was assumed to play a central role in the high moisturizing properties. To conclude, the placenta ferment filtrates developed in this study are beneficial for cosmetic applications.
]]>Fermentation doi: 10.3390/fermentation10020087
Authors: Wenjiao Xue Chen Liu Yao Liu Hao Ding Chao An Shizhe Zhang Saijian Ma Qiwen Zhang
To assess the probiotic potential of strain 68-1 with rutin conversion capabilities, isolated from Chinese traditional Jiangshui, a complete genomic analysis and in vitro tests were conducted. The Oxford Nanopore Technologies (ONT, Oxford, UK)–Illumina (San Diego, CA, USA) hybrid sequencing platform was used for whole genome sequencing and the results showed that strain 68-1 had a chromosome sequence of 3,482,151 bp, with 46.53% GC content and five plasmids with a sequence length ranging from 2009 bp to 48,711 bp. Strain 68-1 was identified as Lactiplantibacillus pentosus based on the whole genome sequence. A total of 133 genes encoding for carbohydrate-active enzymes (CAZymes) were identified and genes that may be involved in rutin conversion were found in the L. pentosus 68-1 genome. L. pentosus 68-1 showed excellent tolerance to gastrointestinal juice and adhesion properties, and corresponding genes were identified. In addition, L. pentosus 68-1 exhibited strong antibacterial and antifungal activity, where organic acids may play a crucial role in its antagonistic ability. Moreover, the gene cluster for plantaricin_EF production was detected. No high virulence factor was found in the L. pentosus 68-1 genome and no hemolytic effect was observed. In addition, L. pentosus 68-1 showed resistance to ampicillin, gentamycin, and kanamycin, and the genomic analysis indicated that horizontal ARG transfer should not be possible. The results show that L. pentosus 68-1 could be developed as a novel probiotic candidate to improve rutin bioavailability in the food and feed industry.
]]>Fermentation doi: 10.3390/fermentation10020088
Authors: Yuanping Zhong Wenqing Yang Qian Zhuo Zhi Cao Qinghua Chen Liren Xiao
Organic solid waste is a renewable resource as it can be transformed into a valuable product through various technologies. Composting is considered to be the most economical and effective technology for treating organic solid waste, but excessive amounts of heavy metals in organic solid waste compost are harmful to the environment. The current focus is on the addition of heavy metal passivators to organic solid waste to reduce the mobility and biotoxicity of heavy metals in situ or ex situ. The aims of this paper are to provide an overview of heavy metal passivators and their passivation mechanisms in the field of organic solid waste composting and to provide a reference for research on the control of heavy metal pollution in the treatment of organic solid waste.
]]>Fermentation doi: 10.3390/fermentation10020086
Authors: Varavut Tanamool Prayoon Enmak Pakawadee Kaewkannetra
Biodiesel produced from waste cooking oil (WCO) is on the rise and inevitably leads to issues in managing glycerol waste. Due to the presence of colour, odour and other minor compounds, the refining costs for this type of glycerol are higher and uneconomical. The potential of biodiesel-derived glycerol waste (BDGW) obtained from WCO to produce the highly added product of docosahexaenoic acid (DHA), also known as omega-3 polyunsaturated fatty acid, via the marine microalga of Schizochytrium limacinum ATCC MYA-1381 under aerobic batch fermentation was investigated. Cell growth, as well as DHA production, were performed under various operating conditions, including aeration rates and BDGW concentrations. The effect of the substrate type on cell growth and DHA yield was evaluated. The optimum operating condition was obtained when the air flow of a 0.25 vvm and 50 g/L of the glycerol concentration was fed into the fermenter and maximum cell dry weight (11.40 g/L) and DHA yield (665.52 mg/g) were achieved. However, cell growth and DHA yield were not significantly different when S. limacinum was grown using various carbon sources. Successfully, it clearly demonstrates that the BDGW can be used as a cheap carbon source for DHA production via marine microalgae using aerobic batch fermentation.
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