Recent advancements in various steps of ethanol, butanol, and isobutanol productions from woody materials
ABSTRACT In this review, the recent advancements and technical challenges associated with the production of ethanol, butanol and isobutanol via bioconversion routes from celluloses of woody materials are reviewed. Physicochemical processes, e.g. steam explosion, seem to be the most viableprocessfor pretreating woody materials. Although enzymatic hydrolysis is selective, it is rather a slow process. Acid hydrolysis is a relatively fast process with a high yield, but it produces inhibitory compounds of fermentation, which necessitates a detoxification process prior to the fermentation. Presently, the major challenges in the production of ethanol,butanol and isobutanol via biological conversions are the ratherlow production yield and the sensitivity of microorganisms to the presence of inhibitors and productsin fermentation media. In this study, the recent advancements in the applications of S. cerevisiae,C. Acetobutylicum and C. glutamicumas, the most promising microorganisms, for ethanol, butanol and isobutanol production arealso discussed. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 2013.
SourceAvailable from: Mehdi Dashtban[Show abstract] [Hide abstract]
ABSTRACT: Lignocellulosic materials can be utilized in the production of platform chemicals such as hydroxymethylfurfural (HMF). HMF production has been investigated in various aqueous, solvent, biphasic and ionic liquid systems. Aqueous medium usually suffers from a low HMF yield (usually 50 to 60% while using fructose as feedstock) due to the production of by-products and the decomposition of HMF. A higher HMF production was achieved by applying biphasic systems, however, these systems face some technical challenges including solvent recovery, process complexity and environmental issues, which prevent its practical implementations at industrial scales. The unique properties of ionic liquids (IL)s make them promising solvents for producing HMF from polysaccharides. In this review, the effects of various parameters such as catalysts, solvents, and process conditions on the production of HMF from various lignocellulosic feedstocks as well as systems developed for purifying HMF after production are discussed. Generally, the yield of HMF production in the IL systems was higher than 80% when fructose was used as the raw material, but was less than 50% when cellulose or other polysaccharides were used. However, the IL system is complicated and has a challenging recovery process. The proposed IL systems are also not environmentally friendly. The main emphasis of this paper is on the industrial applicability of proposed processes for producing HMF.RSC Advances 01/2014; 4(4):2037. DOI:10.1039/c3ra45396k · 3.71 Impact Factor
Article: Biobutanol from cheese whey[Show abstract] [Hide abstract]
ABSTRACT: At present, due to environmental and economic concerns, it is urgent to evolve efficient, clean and secure systems for the production of advanced biofuels from sustainable cheap sources. Biobutanol has proved better characteristics than the more widely used bioethanol, however the main disadvantage of biobutanol is that it is produced in low yield and titer by ABE (acetone-butanol-ethanol) fermentation, this process being not competitive from the economic point of view. In this review we summarize the natural metabolic pathways for biobutanol production by Clostridia and yeasts, together with the metabolic engineering efforts performed up to date with the aim of either enhancing the yield of the natural producer Clostridia or transferring the butanol production ability to other hosts with better attributes for industrial use and facilities for genetic manipulation. Molasses and starch-based feedstocks are main sources for biobutanol production at industrial scale hitherto. We also review herewith (and for the first time up to our knowledge) the research performed for the use of whey, the subproduct of cheese making, as another sustainable source for biobutanol production. This represents a promising alternative that still needs further research. The use of an abundant waste material like cheese whey, that would otherwise be considered an environmental pollutant, for biobutanol production, makes economy of the process more profitable.Microbial Cell Factories 12/2015; 14(1):200. DOI:10.1186/s12934-015-0200-1 · 4.25 Impact Factor
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ABSTRACT: The yeast Saccharomyces cerevisiae remains a highly relevant experimental model in the field of toxicogenomics and is an important microbial cell factory for the production of added-value chemicals and biofuels. Its deep functional characterization coupled with the straightforward exploitation of Omic approaches and metabolic engineering, at the frontline of systems and synthetic biology, is instrumental to obtain mechanistic insights into the response to multiple toxicants and for the development of robust industrial strains. This critical review focuses on the current field, ranging from the identification of toxicological outcomes of exposure to environmental toxicants, with impact in risk assessment, bioremediation and plant biotechnology, to the improvement of biomass-based biorefinery processes, with applications in pharmacology and in the food and beverages industry. Copyright © 2015 Elsevier Ltd. All rights reserved.Current Opinion in Biotechnology 06/2015; 33. DOI:10.1016/j.copbio.2015.03.001 · 8.04 Impact Factor