Advances in Microalgae Biotechnology

A special issue of Biology (ISSN 2079-7737). This special issue belongs to the section "Biotechnology".

Deadline for manuscript submissions: closed (1 July 2023) | Viewed by 30982

Special Issue Editors

Department of Engineering, Universidad de Almería, Almeria, Spain
Interests: microalgae biotechnology; CO2 capture; wastewater, energy, food
Department of Chemical Engineering, University of Almería, 04120 Almería, Spain
Interests: photobioreactors; biomass; chemical engineering

Special Issue Information

Dear Colleagues,

For thousands of years, agriculture has been shaped to address the needs of sustaining human life. However, current challenges in producing food and energy for an ever-growing population, deep within an environmental crisis brought on by decades of industrial and agricultural practices, are vast and urgent. Today, scientists are looking at microalgae more than ever, as these rapidly growing unicellular species could be key to sustainable growth. Current hot topics in microalgae biotechnology research are photobioreactors, nutrient removal, flocculation, bioactive pigments and molecules, and hydrogen production, among others. Therefore, biomass production, bioremediation and wastewater treatment, food, pharmacological and cosmetics industries, and energy production, are the main fields of interest.

Advances in microalgae biotechnology concerning fields from the production and applications of metabolites, including production optimization, recovery, production of different metabolites and products, and their applications, to bioremediation applications of microalgae are taking place. This special issue will focus on original papers covering areas of microalgae biotechnology that present advances in those fields.

Dr. Cynthia Victoria González-López
Dr. Celeste Brindley
Guest Editors

Manuscript Submission Information

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Keywords

  • microalgae
  • biotechnology
  • photobioreactors
  • bioremediation
  • wastewater
  • energy
  • food
  • bioactive molecules
  • recovery

Published Papers (12 papers)

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Research

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20 pages, 14868 KiB  
Article
Bioactive Compounds with Pesticide Activities Derived from Aged Cultures of Green Microalgae
by Alethia A. Brito-Bello and Damar Lopez-Arredondo
Biology 2023, 12(8), 1149; https://0-doi-org.brum.beds.ac.uk/10.3390/biology12081149 - 19 Aug 2023
Viewed by 1563
Abstract
The excessive use of synthetic pesticides has caused environmental problems and human health risks and increased the development of resistance in several organisms. Allelochemicals, secondary metabolites produced as part of the defense mechanisms in plants and microorganisms, are an attractive alternative to replace [...] Read more.
The excessive use of synthetic pesticides has caused environmental problems and human health risks and increased the development of resistance in several organisms. Allelochemicals, secondary metabolites produced as part of the defense mechanisms in plants and microorganisms, are an attractive alternative to replace synthetic pesticides to remediate these problems. Microalgae are natural producers of a wide range of allelochemicals. Thus, they provide new opportunities to identify secondary metabolites with pesticide activities and an alternative approach to discover new modes of action and circumvent resistance. We screened 10 green microalgae strains belonging to the Chlorophyta phylum for their potential to inhibit the growth of photosynthetic and nonphotosynthetic organisms. Bioassays were established to assess microalgae extracts’ effectiveness in controlling the growth of Chlorella sorokiniana, Arabidopsis thaliana, Amaranthus palmeri, and the model nematode Caenorhabditis elegans. All tested strains exhibited herbicidal, nematocidal, or algicidal activities. Importantly, methanol extracts of a Chlamydomonas strain effectively controlled the germination and growth of a glyphosate-resistant A. palmeri biotype. Likewise, some microalgae extracts effectively killed C. elegans L1 larvae. Comprehensive metabolic profiling using LC-MS of extracts with pesticide activities showed that the metabolite composition of Chlamydomonas, Chlorella, and Chloroidium extracts is diverse. Molecules such as fatty acids, isoquinoline alkaloids, aldehydes, and cinnamic acids were more abundant, suggesting their participation in the pesticide activities. Full article
(This article belongs to the Special Issue Advances in Microalgae Biotechnology)
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13 pages, 1027 KiB  
Article
Comparative Evaluation of Chlorella vulgaris and Anabaena variabilis for Phycoremediation of Polluted River Water: Spotlighting Heavy Metals Detoxification
by Md. Shakir Ahammed, Md. Abdul Baten, Muhammad Aslam Ali, Shahin Mahmud, Md. Sirajul Islam, Bhim Sen Thapa, Md. Aminul Islam, Md. Alim Miah and Tanmoy Roy Tusher
Biology 2023, 12(5), 675; https://0-doi-org.brum.beds.ac.uk/10.3390/biology12050675 - 01 May 2023
Cited by 2 | Viewed by 2046
Abstract
This study investigated the phycoremediation abilities of Chlorella vulgaris (microalga) and Anabaena variabilis (cyanobacterium) for the detoxification of polluted river water. Lab-scale phycoremediation experiments were conducted for 20 days at 30 °C using the microalgal and cyanobacterial strains and water samples collected from [...] Read more.
This study investigated the phycoremediation abilities of Chlorella vulgaris (microalga) and Anabaena variabilis (cyanobacterium) for the detoxification of polluted river water. Lab-scale phycoremediation experiments were conducted for 20 days at 30 °C using the microalgal and cyanobacterial strains and water samples collected from the Dhaleswari river in Bangladesh. The physicochemical properties such as electrical conductivity (EC), total dissolved solids (TDS), biological oxygen demand (BOD), hardness ions, and heavy metals of the collected water samples indicated that the river water is highly polluted. The results of the phycoremediation experiments demonstrated that both microalgal and cyanobacterial species significantly reduced the pollutant load and heavy metal concentrations of the river water. The pH of the river water was significantly raised from 6.97 to 8.07 and 8.28 by C. vulgaris and A. variabilis, respectively. A. variabilis demonstrated higher efficacy than C. vulgaris in reducing the EC, TDS, and BOD of the polluted river water and was more effective at reducing the pollutant load of SO42− and Zn. In regard to hardness ions and heavy metal detoxification, C. vulgaris performed better at removing Ca2+, Mg2+, Cr, and Mn. These findings indicate that both microalgae and cyanobacteria have great potential to remove various pollutants, especially heavy metals, from the polluted river water as part of a low-cost, easily controllable, environmentally friendly remediation strategy. Nevertheless, the composition of polluted water should be assessed prior to the designing of microalgae- or cyanobacteria-based remediation technology, since the pollutant removal efficiency is found to be species dependent. Full article
(This article belongs to the Special Issue Advances in Microalgae Biotechnology)
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13 pages, 2290 KiB  
Article
Sulfated Polysaccharides from Chaetoceros muelleri: Macromolecular Characteristics and Bioactive Properties
by Valeria Miranda-Arizmendi, Diana Fimbres-Olivarria, Anselmo Miranda-Baeza, Karla Martínez-Robinson, Agustín Rascón-Chu, Yubia De Anda-Flores, Jaime Lizardi-Mendoza, Mayra A. Mendez-Encinas, Francisco Brown-Bojorquez, Rafael Canett-Romero and Elizabeth Carvajal-Millan
Biology 2022, 11(10), 1476; https://0-doi-org.brum.beds.ac.uk/10.3390/biology11101476 - 08 Oct 2022
Cited by 3 | Viewed by 1766
Abstract
In the present study, a culture of Chaetoceros muelleri, a cosmopolitan planktonic diatom microalga present in the Sea of Cortez, was established under controlled laboratory conditions. A sulfated polysaccharide (CMSP) extraction was carried out from the biomass obtained, resulting in a yield [...] Read more.
In the present study, a culture of Chaetoceros muelleri, a cosmopolitan planktonic diatom microalga present in the Sea of Cortez, was established under controlled laboratory conditions. A sulfated polysaccharide (CMSP) extraction was carried out from the biomass obtained, resulting in a yield of 2.2% (w/w of dry biomass). The CMSP sample was analyzed by Fourier transform infrared spectroscopy, showing bands ranging from 3405 to 590 cm−1 and a sulfate substitution degree of 0.10. Scanning electron microscopy with elemental analysis revealed that the CMSP particles are irregularly shaped with non-acute angles and contain sulfur. High-performance liquid chromatography coupled to a dynamic light-scattering detector yielded molecular weight (Mw), polydispersity index (PDI), intrinsic viscosity [η], and hydrodynamic radius (Rh) values of 4.13 kDa, 2.0, 4.68 mL/g, and 1.3 nm, respectively, for the CMSP. This polysaccharide did not present cytotoxicity in CCD-841 colon cells. The antioxidant activity and the glycemic index of the CMSP were 23% and 49, respectively, which gives this molecule an added value by keeping low glycemic levels and exerting antioxidant activity simultaneously. Full article
(This article belongs to the Special Issue Advances in Microalgae Biotechnology)
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14 pages, 2296 KiB  
Article
Heterologous Expression of Cyanobacterial Cyanase Gene (CYN) in Microalga Chlamydomonas reinhardtii for Bioremediation of Cyanide Pollution
by Shaimaa S. Sobieh, Rasha Abed El-Gammal, Wafaa S. Abu El-Kheir, Alia A. El-Sheimy, Alaa A. Said and Yassein M. El-Ayouty
Biology 2022, 11(10), 1420; https://0-doi-org.brum.beds.ac.uk/10.3390/biology11101420 - 29 Sep 2022
Cited by 2 | Viewed by 1619
Abstract
Recombinant DNA technology offered the creation of new combinations of DNA segments that are not found together in nature. The present study aimed to produce an ecofriendly bioremediation model to remediate cyanide pollution from a polluted marine system. Cyanide is a known toxic [...] Read more.
Recombinant DNA technology offered the creation of new combinations of DNA segments that are not found together in nature. The present study aimed to produce an ecofriendly bioremediation model to remediate cyanide pollution from a polluted marine system. Cyanide is a known toxic compound produced through natural and anthropogenic activities. An Agrobacterium-tumefaciens-mediated genetic transformation technique was used to generate transformed Chlamydomonas reinhardtii using plant expression vector pTRA-K-cTp carries isolated coding sequence of the cyanobacterial cyanase gene (CYN) isolated from Synechococcus elongatus (PCC6803). qRT-PCR analysis showed the overexpression of CYN in transgenic C. reinhardtii, as compared with the respective wild type. Growth parameters and biochemical analyses were performed under cyanide stress conditions using transgenic and wild C. reinhardtii for evaluating the effect of the presence of the cyanobacterial cyanase gene in algae. The transgenic C. reinhardtii strain (TC. reinhardtii-2) showed promising results for cyanide bioremediation in polluted water samples. Cyanide depletion assays and algal growth showed a significant resistance in the transgenic type against cyanide stress, as compared to the wild type. Genetically modified alga showed the ability to phytoremediate a high level of potassium cyanide (up to150 mg/L), as compared to the wild type. The presence of the CYN gene has induced a protection response in TC. Reinhardtii-2, which was shown in the results of growth parameter analyses. Therefore, the present study affirms that transgenic C. reinhardtii by the CYN coding gene is a potential effective ecofriendly bioremediator model for the remediation of cyanide pollutants in fresh water. Full article
(This article belongs to the Special Issue Advances in Microalgae Biotechnology)
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18 pages, 3101 KiB  
Article
Photosynthesis Monitoring in Microalgae Cultures Grown on Municipal Wastewater as a Nutrient Source in Large-Scale Outdoor Bioreactors
by Jiří Masojídek, Cintia Gómez-Serrano, Karolína Ranglová, Bernardo Cicchi, Ángel Encinas Bogeat, João A. Câmara Manoel, Ana Sanches Zurano, Ana Margarita Silva Benavides, Marta Barceló-Villalobos, Victor A. Robles Carnero, Vince Ördög, Juan Luis Gómez Pinchetti, Lajos Vörös, Zouhayr Arbib, Frank Rogalla, Giuseppe Torzillo, Félix Lopez Figueroa and Francisco Gabriel Acién-Fernándéz
Biology 2022, 11(10), 1380; https://0-doi-org.brum.beds.ac.uk/10.3390/biology11101380 - 22 Sep 2022
Cited by 12 | Viewed by 2169
Abstract
Microalgae cultures were used for a WW treatment to remediate nutrients while producing biomass and recycling water. In these trials, raceway ponds (RWPs; 1 and 0.5 ha) were located next to a municipal (WW) treatment plant in Mérida, Spain. The ponds were used [...] Read more.
Microalgae cultures were used for a WW treatment to remediate nutrients while producing biomass and recycling water. In these trials, raceway ponds (RWPs; 1 and 0.5 ha) were located next to a municipal (WW) treatment plant in Mérida, Spain. The ponds were used for continuous, all-year-round microalgae production using WW as a source of nutrients. Neither CO2 nor air was supplied to cultures. The objective was to validate photosynthesis monitoring techniques in large-scale bioreactors. Various in-situ/ex-situ methods based on chlorophyll fluorescence and oxygen evolution measurements were used to follow culture performance. Photosynthesis variables gathered with these techniques were compared to the physiological behavior and growth of cultures. Good photosynthetic activity was indicated by the build-up of dissolved oxygen concentration up to 380% saturation, high photochemical yield (Fv/Fm = 0.62–0.71), and relative electron transport rate rETR between 200 and 450 μmol e m−2 s−1 at midday, which resulted in biomass productivity of about 15–25 g DW m−2 day−1. The variables represent reliable markers reflecting the physiological status of microalgae cultures. Using waste nutrients, the biomass production cost can be significantly decreased for abundant biomass production in large-scale bioreactors, which can be exploited for agricultural purposes. Full article
(This article belongs to the Special Issue Advances in Microalgae Biotechnology)
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19 pages, 4812 KiB  
Article
Simulation and Techno-Economical Evaluation of a Microalgal Biofertilizer Production Process
by Juan Miguel Romero-García, Cynthia Victoria González-López, Celeste Brindley, José María Fernández-Sevilla and Francisco Gabriel Acién-Fernández
Biology 2022, 11(9), 1359; https://0-doi-org.brum.beds.ac.uk/10.3390/biology11091359 - 16 Sep 2022
Cited by 6 | Viewed by 2171
Abstract
Due to population growth in the coming years, an increase in agricultural production will soon be mandatory, thus requiring fertilizers that are more environmentally sustainable than the currently most-consumed fertilizers since these are important contributors to climate change and water pollution. The objective [...] Read more.
Due to population growth in the coming years, an increase in agricultural production will soon be mandatory, thus requiring fertilizers that are more environmentally sustainable than the currently most-consumed fertilizers since these are important contributors to climate change and water pollution. The objective of this work is the techno-economic evaluation of the production of biofertilizer concentrated in free amino acids from microalgal biomass produced in a wastewater treatment plant, to determine its economic viability. A process proposal has been made in six stages that have been modelled and simulated with the ASPEN Plus simulator. A profitability analysis has been carried out using a Box–Behnken-type response surface statistical design with three factors—the cost of the biomass sludge, the cost of the enzymes, and the sale price of the biofertilizer. It was found that the most influential factor in profitability is the sale price of the biofertilizer. According to a proposed representative base case, in which the cost of the biomass sludge is set to 0.5 EUR/kg, the cost of the enzymes to 20.0 EUR/kg, and the sale price of the biofertilizer to 3.5 EUR/kg, which are reasonable costs, it is concluded that the production of the biofertilizer would be economically viable. Full article
(This article belongs to the Special Issue Advances in Microalgae Biotechnology)
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15 pages, 1533 KiB  
Article
Biorefinery Approach Applied to the Production of Food Colourants and Biostimulants from Oscillatoria sp.
by Ainoa Morillas-España, Ruperto Bermejo, Roberto Abdala-Díaz, Ángela Ruiz, Tomás Lafarga, Gabriel Acién and José María Fernández-Sevilla
Biology 2022, 11(9), 1278; https://0-doi-org.brum.beds.ac.uk/10.3390/biology11091278 - 28 Aug 2022
Cited by 1 | Viewed by 1509
Abstract
In this study, a biorefinery based on Oscillatoria sp. is developed to produce high-value compounds such as C-phycocyanin, used in food colourant applications, and biostimulants, used in agriculture-related applications. First, the Oscillatoria biomass production was optimized at a pilot scale in an open [...] Read more.
In this study, a biorefinery based on Oscillatoria sp. is developed to produce high-value compounds such as C-phycocyanin, used in food colourant applications, and biostimulants, used in agriculture-related applications. First, the Oscillatoria biomass production was optimized at a pilot scale in an open raceway reactor, with biomass productivities equivalent to 52 t/ha·year being achieved using regular fertilizers as the nutrient source. The biomass produced contained 0.5% C-phycocyanins, 95% of which were obtained after freeze–thawing and extraction at pH 6.5 and ionic strength (FI) 100 mM, with a purity ratio of 0.71 achieved in the final extract. This purity ratio allows for use of the extract directly as a food colourant. Then, the extract’s colourant capacity on different beverages was evaluated. The results confirm that C-phycocyanin concentrations ranging from 22 to 106 mg/L produce colours similar to commercial products, thus avoiding the need for synthetic colourants. The colour remained stable for up to 12 days. Moreover, the safety of the extracted C-phycocyanin was confirmed through toxicity tests. The waste biomass was evaluated for use as a biostimulant, with the results confirming a relevant auxin-like positive effect. Finally, an economic analysis was conducted to evaluate different scenarios. The results confirm that the production of both C-phycocyanin and biostimulants is the best scenario from an economic standpoint. Therefore, the developed biomass processing scheme provides an opportunity to expand the range of commercial applications for microalgae-related processes. Full article
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24 pages, 2256 KiB  
Article
Current Concentrations of Zn, Cu, and As in Piggery Wastewater Compromise Nutrient Removals in Microalgae–Bacteria Photobioreactors Due to Altered Microbial Communities
by Javiera Collao, Pedro Antonio García-Encina, Saúl Blanco, Silvia Bolado-Rodríguez and Nuria Fernandez-Gonzalez
Biology 2022, 11(8), 1176; https://0-doi-org.brum.beds.ac.uk/10.3390/biology11081176 - 05 Aug 2022
Cited by 8 | Viewed by 2152
Abstract
The treatment of pig manure is a major environmental issue, and photobioreactors containing consortia of microalgae and bacteria have proven to be a promising and sustainable treatment alternative. This work studies the effect of Cu, Zn and As, three toxic elements frequently present [...] Read more.
The treatment of pig manure is a major environmental issue, and photobioreactors containing consortia of microalgae and bacteria have proven to be a promising and sustainable treatment alternative. This work studies the effect of Cu, Zn and As, three toxic elements frequently present in piggery wastewater, on the performance and microbiome of photobioreactors. After dopage with Zn (100 mg/L), Cu (100 mg/L), and As (500 µg/L), the high biomass uptake of Zn (69–81%) and Cu (81–83%) decreased the carbon removal in the photobioreactors, inhibited the growth of Chlorella sp., and affected heterotrophic bacterial populations. The biomass As uptake result was low (19%) and actually promoted microalgae growth. The presence of Cu and As decreased nitrogen removal, reducing the abundance of denitrifying bacterial populations. The results showed that metal(loid)s significantly affected 24 bacterial genera and that they did not recover after exposure. Therefore, this study makes an important contribution on the impact of the presence of metal(loid)s in piggery wastewater that compromises the overall performance of PBRs, and so, the environmental and health impact of treated effluents. Full article
(This article belongs to the Special Issue Advances in Microalgae Biotechnology)
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16 pages, 1001 KiB  
Article
Promising Biomolecules with High Antioxidant Capacity Derived from Cryptophyte Algae Grown under Different Light Conditions
by Maryam Abidizadegan, Jaanika Blomster, David Fewer and Elina Peltomaa
Biology 2022, 11(8), 1112; https://0-doi-org.brum.beds.ac.uk/10.3390/biology11081112 - 26 Jul 2022
Cited by 2 | Viewed by 1675
Abstract
The accumulation and production of biochemical compounds in microalgae are influenced by available light quality and algal species-specific features. In this study, four freshwater cryptophyte strains (Cryptomonas ozolinii, C. pyrenoidifera, C. curvata, and C. sp. (CPCC 336)) and one [...] Read more.
The accumulation and production of biochemical compounds in microalgae are influenced by available light quality and algal species-specific features. In this study, four freshwater cryptophyte strains (Cryptomonas ozolinii, C. pyrenoidifera, C. curvata, and C. sp. (CPCC 336)) and one marine strain (Rhodomonas salina) were cultivated under white (control), blue, and green (experimental conditions) lights. Species-specific responses to light quality were detected, i.e., the color of light significantly affected cryptophyte biomass productivity and biochemical compositions, but the optimal light for the highest chemical composition with high antioxidant capacity was different for each algal strain. Overall, the highest phycoerythrin (PE) content (345 mg g−1 dry weight; DW) was reached by C. pyrenoidifera under green light. The highest phenolic (PC) contents (74, 69, and 66 mg g−1 DW) were detected in C. curvata under control conditions, in C. pyrenoidifera under green light, and in C. ozolinii under blue light, respectively. The highest exopolysaccharide (EPS) content (452 mg g−1 DW) was found in C. curvata under the control light. In terms of antioxidant activity, the biochemical compounds from the studied cryptophytes were highly active, with IC50 -values < 50 µg mL−1. Thus, in comparison to well-known commercial microalgal species, cryptophytes could be considered a possible candidate for producing beneficial biochemical compounds. Full article
(This article belongs to the Special Issue Advances in Microalgae Biotechnology)
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14 pages, 2349 KiB  
Article
Biostimulant Capacity of Chlorella and Chlamydopodium Species Produced Using Wastewater and Centrate
by Ainoa Morillas-España, Ángela Ruiz-Nieto, Tomás Lafarga, Gabriel Acién, Zouhayr Arbib and Cynthia V. González-López
Biology 2022, 11(7), 1086; https://0-doi-org.brum.beds.ac.uk/10.3390/biology11071086 - 20 Jul 2022
Cited by 16 | Viewed by 2059
Abstract
The aim of the present study was to assess the potential of producing four microalgal strains using secondary-treated urban wastewater supplemented with centrate, and to evaluate the biostimulant effects of several microalgal extracts obtained using water and sonication. Four strains were studied: Chlorella [...] Read more.
The aim of the present study was to assess the potential of producing four microalgal strains using secondary-treated urban wastewater supplemented with centrate, and to evaluate the biostimulant effects of several microalgal extracts obtained using water and sonication. Four strains were studied: Chlorella vulgaris UAL-1, Chlorella sp. UAL-2, Chlorella vulgaris UAL-3, and Chlamydopodium fusiforme UAL-4. The highest biomass productivity was found for C. fusiforme, with a value of 0.38 ± 0.01 g·L−1·day−1. C. vulgaris UAL-1 achieved a biomass productivity of 0.31 ± 0.03 g·L−1·day−1 (the highest for the Chlorella genus), while the N-NH4+, N-NO3, and P-PO43− removal capacities of this strain were 51.9 ± 2.4, 0.8 ± 0.1, and 5.7 ± 0.3 mg·L−1·day−1, respectively. C. vulgaris UAL-1 showed the greatest potential for use as a biostimulant—when used at a concentration of 0.1 g·L−1, it increased the germination index of watercress seeds by 3.5%. At concentrations of 0.5 and 2.0 g·L−1, the biomass from this microalga promoted adventitious root formation in soybean seeds by 220% and 493%, respectively. The cucumber expansion test suggested a cytokinin-like effect from C. vulgaris UAL-1; it was also the only strain that promoted the formation of chlorophylls in wheat leaves. Overall, the results of the present study suggest the potential of producing C. vulgaris UAL-1 using centrate and wastewater as well as the potential utilisation of its biomass to develop high-value biostimulants. Full article
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16 pages, 1583 KiB  
Article
Optimisation of Biomass Production and Nutritional Value of Two Marine Diatoms (Bacillariophyceae), Skeletonema costatum and Chaetoceros calcitrans
by Carolina R. V. Bastos, Inês B. Maia, Hugo Pereira, João Navalho and João C. S. Varela
Biology 2022, 11(4), 594; https://0-doi-org.brum.beds.ac.uk/10.3390/biology11040594 - 14 Apr 2022
Cited by 8 | Viewed by 3498
Abstract
S. costatum and C. calcitrans are two cosmopolitan high-value centric diatoms, with a rich nutritional profile. The following work optimised the culture medium of S. costatum and C. calcitrans cultures, respectively, in a stepwise process as follows: 2.4 mM and 1.2 mM of [...] Read more.
S. costatum and C. calcitrans are two cosmopolitan high-value centric diatoms, with a rich nutritional profile. The following work optimised the culture medium of S. costatum and C. calcitrans cultures, respectively, in a stepwise process as follows: 2.4 mM and 1.2 mM of silicate, 4 mM of nitrate, 100 µM of phosphate, 20 and 80 µM iron, and 0.5 mL L−1 of micronutrients. The results that were obtained revealed an increase in biomass productivity with a 1.8- and 3.2-fold increase in biomass that was produced by S. costatum and C. calcitrans, respectively. The biochemical profile showed an increase in high-value PUFAs such as 2.6-fold and 2.3-fold increase in EPA for S. costatum and C. calcitrans, respectively, whilst a 2.6-fold increase in DHA was detected in S. costatum cultures. The present work provides the basic tools for the industrial cultivation of S. costatum and C. calcitrans with enhanced productivity as well as improved biomass quality, two factors which are highly relevant for a more effective application of these diatoms to aquaculture and nutraceutical production. Full article
(This article belongs to the Special Issue Advances in Microalgae Biotechnology)
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Review

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27 pages, 13351 KiB  
Review
Microalgae-Based Biorefineries: Challenges and Future Trends to Produce Carbohydrate Enriched Biomass, High-Added Value Products and Bioactive Compounds
by Eugenia J. Olguín, Gloria Sánchez-Galván, Imilla I. Arias-Olguín, Francisco J. Melo, Ricardo E. González-Portela, Lourdes Cruz, Roberto De Philippis and Alessandra Adessi
Biology 2022, 11(8), 1146; https://0-doi-org.brum.beds.ac.uk/10.3390/biology11081146 - 29 Jul 2022
Cited by 31 | Viewed by 6486
Abstract
Microalgae have demonstrated a large potential in biotechnology as a source of various macromolecules (proteins, carbohydrates, and lipids) and high-added value products (pigments, poly-unsaturated fatty acids, peptides, exo-polysaccharides, etc.). The production of biomass at a large scale becomes more economically feasible when it [...] Read more.
Microalgae have demonstrated a large potential in biotechnology as a source of various macromolecules (proteins, carbohydrates, and lipids) and high-added value products (pigments, poly-unsaturated fatty acids, peptides, exo-polysaccharides, etc.). The production of biomass at a large scale becomes more economically feasible when it is part of a biorefinery designed within the circular economy concept. Thus, the aim of this critical review is to highlight and discuss challenges and future trends related to the multi-product microalgae-based biorefineries, including both phototrophic and mixotrophic cultures treating wastewater and the recovery of biomass as a source of valuable macromolecules and high-added and low-value products (biofertilizers and biostimulants). The therapeutic properties of some microalgae-bioactive compounds are also discussed. Novel trends such as the screening of species for antimicrobial compounds, the production of bioplastics using wastewater, the circular economy strategy, and the need for more Life Cycle Assessment studies (LCA) are suggested as some of the future research lines. Full article
(This article belongs to the Special Issue Advances in Microalgae Biotechnology)
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