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Biotechnological Processes for Biofuel Production

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A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "A4: Bio-Energy".

Deadline for manuscript submissions: closed (31 December 2022) | Viewed by 13890

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Special Issue Editors

Prof. Dr. Antonio Marzocchella

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Guest Editor

Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli Federico II, 80125 Napoli, Italy

Dr. Maria Elena Russo

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Istituto di Scienze e Tecnologie per l’Energia e la Mobilità Sostenibili (STEMS), Consiglio Nazionale delle Ricerche, P.le V. Tecchio 80, 80125 Napoli, Italy
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Special Issue Information

Dear Colleagues,

The portfolio of biofuels produced via biotechnological processes includes liquid (e.g. ethanol, butanol, biodiesel) and gaseous (e.g. bio-methane) fuels. On the one hand, the production of these products is a challenging enterprise that involves a spectrum of knowledge/technologies: bio-feedstock pretreatment (e.g. sugar production from lignocellulos biomass), engineering of microorganisms, fermentation, microalgae culture system, downstream processes (product recovery/purification). Each of these steps assumes a key role for the success of the processes. On the other hand, the emerging multi-feedstock/multi-product biorefinery concept is proposing itself as a winning strategy for the production of energy vectors according to the circular-sustainable economy. In this framework, the production of biofuels can be made economically and environmentally sustainable by the use of carbonaceous wastes as a renewable feedstock and by the simultaneous production of high added value products (e.g. bulk chemicals and bio-commodities for food, and pharma/nutraceutical industries).

This Special Issue aims to present the state of the art of recent advances in biotechnological processes that contribute to open issues in the production of biofuels. Contributions regarding processes and technologies, research for advanced feedstock pretreatment, fermentation, upstream/downstream operations, and their integration are highly encouraged. Studies regarding strategies integrating biofuel production with bio-feedstock exploitation and high-value molecule production within a sustainable framework are welcome.

Prof. Dr. Antonio Marzocchella
Dr. Maria Elena Russo
Guest Editors

Manuscript Submission Information

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Keywords

Biofuel
Biorefinery
Biomass
Pretreatment
Hydrolysis
Enzyme
Fermentation
Downstream
Sustainability

Published Papers (5 papers)

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Research

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17 pages, 5065 KiB

Open AccessArticle

Continuous Bioethanol Production by Fungi and Yeast Working in Tandem

by Valeria Rahamim, Faina Nakonechny, Aharon Azagury and Marina Nisnevitch

Energies 2022, 15(12), 4338; https://0-doi-org.brum.beds.ac.uk/10.3390/en15124338 - 14 Jun 2022

Cited by 3 | Viewed by 2633

Abstract

Biofuel is considered one of the most viable alternatives to fossil fuels derived from the dwindling petroleum resources that damage the environment. Bioethanol could be manufactured from agricultural wastes, thus providing inexpensive natural resources. Several strategies have been utilized to convert lignocellulosic hydrolysate to bioethanol with various suspended microorganisms. In this study, we alternatively propose to encapsulate these microorganisms in bioreactor setups. An immobilized cell system can provide resistance to the inhibitors present in hydrolysates, enhance productivity, facilitate the separation process, and improve microorganism recycling. Herein, we developed a continuous bioethanol production process by encapsulating three types of micro-organisms: T. reesei, S. cerevisiae, and P. stipitis. These microorganisms were encapsulated in SBP (“Small Bioreactor Platform”) capsules and tested for their viability post encapsulation, biological activity, and bioethanol production. Encapsulating microorganisms in SBP capsules provided a confined protective environment for the microorganisms, facilitated their acclimation, and ensured their long-term prosperity and activity. An additional significant benefit of utilizing SBP capsules was the simultaneous availability of saccharification and fermentation over a very long time—about 2.5–3 months—with no need to renew the cells or encapsulating matrices. Two different configurations were tested. The first one consisted of columns packed with fungal cells and specific yeast cells together. In the second configuration, the fungal cells were separated from the yeast cells into two columns in series. The presented systems achieved an efficiency of 60–70%, suggesting the long-term prosperity and uninterrupted metabolic activity of the microorganisms. Full article

(This article belongs to the Special Issue Biotechnological Processes for Biofuel Production)

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19 pages, 5991 KiB

Open AccessArticle

Comparative Study on Quality of Fuel Pellets from Switchgrass Treated with Different White-Rot Fungi

by Onu Onu Olughu, Lope G. Tabil, Tim Dumonceaux, Edmund Mupondwa and Duncan Cree

Energies 2021, 14(22), 7670; https://0-doi-org.brum.beds.ac.uk/10.3390/en14227670 - 16 Nov 2021

Cited by 9 | Viewed by 1601

Abstract

Fungal pretreatment of switchgrass using Phanerochaete chrysosporium (PC), Trametes versicolor 52J (TV52J), and the Trametes versicolor mutant strain (m4D) under solid-state fermentation was conducted to improve its pellet quality. For all three fungal strains, the fermentation temperature had a significant effect (p < 0.05) on pellet unit density and tensile strength. The p-values of the quadratic models for all the response variables showed highly significant regression models (p < 0.01) except for dimensional stability. In addition, 3.1-fold and 2.8-fold increase in pellet tensile strength were obtained from P. chrysosporium- and T. versicolor 52J-treated materials, respectively. Microstructural examination showed that fungal pretreatment reduced pores in the pellets and enhanced pellet particle bonding. Among the fungal strains, PC had the shortest optimum fermentation time (21 d) and most positive impact on the pellet tensile strength and hydrophobicity. Therefore, switchgrass pretreatment using PC has the potential for resolving the challenges of switchgrass pellet transportation and storage and reducing the overall pelletization cost. However, a detailed comparative technoeconomic analysis would be required to make definitive cost comparisons. Full article

(This article belongs to the Special Issue Biotechnological Processes for Biofuel Production)

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12 pages, 2070 KiB

Open AccessArticle

Expression of VHb Improved Lipid Production in Rhodosporidium toruloides

by Shuang Wang, Rasool Kamal, Yue Zhang, Renhui Zhou, Liting Lv, Qitian Huang, Siriguleng Qian, Sufang Zhang and Zongbao Kent Zhao

Energies 2020, 13(17), 4446; https://0-doi-org.brum.beds.ac.uk/10.3390/en13174446 - 27 Aug 2020

Cited by 7 | Viewed by 2270

Abstract

The oleaginous yeast Rhodosporidium toruloides has emerged as a robust host for production of microbial lipids as alternative biofuel feedstocks. Oxygen supply is a limiting factor for microbial lipid production, as lipid biosynthesis is highly oxygen-demanding. Vitreoscilla hemoglobin (VHb) is a protein capable of promoting oxygen delivery for anabolism. In this study, we developed R. toruloides with VHb expression for improved lipid production. The VHb expression cassette was integrated into the R. toruloides chromosome via the Agrobacterium-mediated transformation. In shake flask cultures, the engineered strain 4#-13 produced 34% more lipids than the parental strain did. Results obtained under reduced aeration conditions in 3 L bioreactor showed that lipid titer and lipid yield of the engineered strain 4#-13 were 116% and 71%, respectively, higher than those of the parental strain. Under high cell density culture conditions, the engineered strain 4#-13 grew faster and produced 72% more lipids. Our results demonstrated that the VHb gene is functional in R. toruloides for promoting lipid production. The strains described here may be further engineered by integrating extra genetic parts to attain robust producers for more valuable products. This should improve the economics of microbial lipids to facilitate a sustainable production of biodiesel and other lipid-based biofuels. Full article

(This article belongs to the Special Issue Biotechnological Processes for Biofuel Production)

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12 pages, 1554 KiB

Open AccessFeature PaperArticle

Assessment of the Effect of Nitrogen Concentration on Fermentation and Selection of a Highly Competitive Saccharomyces cerevisiae Strain for Efficient Ethanol Production

by Patricia Portero Barahona, Jesús Martín-Gil, Pablo Martín-Ramos, Ana Briones Pérez and Enrique Javier Carvajal Barriga

Energies 2019, 12(13), 2614; https://0-doi-org.brum.beds.ac.uk/10.3390/en12132614 - 07 Jul 2019

Cited by 3 | Viewed by 3411

Abstract

The optimum nitrogen concentration for media supplementation and strain dominance are aspects of key importance to the industrial production of ethanol with a view to reducing costs and increasing yields. In this work, these two factors were investigated for four ethanologenic Saccharomyces cerevisiae strains (CLQCA-INT-001, CLQCA-INT-005, CLQCA-10-099, and UCLM 325), selected from the screening of 150 isolates, mostly from Ecuadorian yeast biodiversity. The effect of nitrogen concentration was assessed in terms of cellular growth, glucose consumption and ethanol production, and the yeast strains’ dominance was evaluated in continuous co-fermentation with cellular recycling by mitochondrial DNA analyses. Among the four selected yeast strains under study, CLQCA-INT-005 presented the highest glucose consumption at a nitrogen supplement concentration as low as 0.4 g·L⁻¹, attaining an ethanol yield of up to 96.72% in 24 h. The same yeast strain was found to be highly competitive, showing a dominance of 80% after four cycles of fermentation in co-culture. Thus, CLQCA-INT-005 may be deemed as a very promising candidate to be used both at pilot-plant scale and at industrial scale cellulosic ethanol production. Full article

(This article belongs to the Special Issue Biotechnological Processes for Biofuel Production)

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Review

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19 pages, 776 KiB

Open AccessReview

The “Zero Miles Product” Concept Applied to Biofuel Production: A Case Study

by Nikolaj Kaae Kirk, Clara Navarrete, Jakob Ellegaard Juhl, José Luis Martínez and Alessandra Procentese

Energies 2021, 14(3), 565; https://0-doi-org.brum.beds.ac.uk/10.3390/en14030565 - 22 Jan 2021

Cited by 4 | Viewed by 2860

Abstract

To make biofuel production feasible from an economic point of view, several studies have investigated the main associated bottlenecks of the whole production process through approaches such as the “cradle to grave” approach or the Life Cycle Assessment (LCA) analysis, being the main constrains the feedstock collection and transport. Whilst several feedstocks are interesting because of their high sugar content, very few of them are available all year around and moreover do not require high transportation’ costs. This work aims to investigate if the “zero miles” concept could bring advantages to biofuel production by decreasing all the associated transport costs on a locally established production platform. In particular, a specific case study applied to the Technical University of Denmark (DTU) campus is used as example to investigate the advantages and feasibility of using the spent coffee grounds generated at the main cafeteria for the production of bioethanol on site, which can be subsequently used to (partially) cover the campus’ energy demands. Full article

(This article belongs to the Special Issue Biotechnological Processes for Biofuel Production)

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