Journal ArticleDOI
Inhibition of ethanol-producing yeast and bacteria by degradation products produced during pre-treatment of biomass.
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TLDR
The inhibitory effect on ethanol production by yeast and bacteria is presented and the inhibition of volumetric ethanol productivity was found to depend on the amount of methoxyl substituents and hence hydrophobicity (log P).Abstract:
An overview of the different inhibitors formed by pre-treatment of lignocellulosic materials and their inhibition of ethanol production in yeast and bacteria is given. Different high temperature physical pre-treatment methods are available to render the carbohydrates in lignocellulose accessible for ethanol fermentation. The resulting hydrolyzsates contain substances inhibitory to fermentation—depending on both the raw material (biomass) and the pre-treatment applied. An overview of the inhibitory effect on ethanol production by yeast and bacteria is presented. Apart from furans formed by sugar degradation, phenol monomers from lignin degradation are important co-factors in hydrolysate inhibition, and inhibitory effects of these aromatic compounds on different ethanol producing microorganisms is reviewed. The furans and phenols generally inhibited growth and ethanol production rate (QEtOH) but not the ethanol yields (YEtOH) in Saccharomyces cerevisiae. Within the same phenol functional group (aldehyde, ketone, and acid) the inhibition of volumetric ethanol productivity was found to depend on the amount of methoxyl substituents and hence hydrophobicity (log P). Many pentose-utilizing strains Escherichia coli, Pichia stipititis, and Zymomonas mobilis produce ethanol in concentrated hemicellulose liquors but detoxification by overliming is needed. Thermoanaerobacter mathranii A3M3 can grow on pentoses and produce ethanol in hydrolysate without any need for detoxification.read more
Citations
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Journal ArticleDOI
Lignocellulosic biomass for bioethanol production: current perspectives, potential issues and future prospects.
Alya Limayem,Steven C. Ricke +1 more
TL;DR: A review of the major steps involved in cellulosic-based bioethanol processes and potential issues challenging these operations is provided in this paper, where possible solutions and recoveries that could improve bioprocessing are also addressed.
Journal ArticleDOI
Increased tolerance and conversion of inhibitors in lignocellulosic hydrolysates by Saccharomyces cerevisiae
João R. M. Almeida,Tobias Modig,Anneli Petersson,Bärbel Hahn-Hägerdal,Gunnar Lidén,Marie-Francoise Gorwa-Grauslund +5 more
TL;DR: Among the microorganisms that have been evaluated for lignocellulosic hydrolysate ethanol fermentation, the yeast Saccharomyces cerevisiae appears to be the least sensitive.
Journal ArticleDOI
Towards industrial pentose-fermenting yeast strains
Bärbel Hahn-Hägerdal,Kaisa Karhumaa,César Fonseca,Isabel Spencer-Martins,Marie-Francoise Gorwa-Grauslund +4 more
TL;DR: This review summarizes recent research aiming at developing industrial strains of Saccharomyces cerevisiae with the ability to ferment all lignocellulose-derived sugars with the potential of pentose fermentation in improving lignOcellulosic ethanol production.
Book ChapterDOI
Progress and challenges in enzyme development for biomass utilization.
Sandra Merino,Joel R. Cherry +1 more
TL;DR: Advances in enzyme technology for use in the production of biofuels and the challenges that remain are described.
Journal ArticleDOI
Genetic manipulation of lignin reduces recalcitrance and improves ethanol production from switchgrass
Chunxiang Fu,Jonathan R. Mielenz,Xirong Xiao,Yaxin Ge,Choo Hamilton,Miguel Á. Rodríguez,Fang Chen,Marcus Foston,Arthur J. Ragauskas,Joseph H. Bouton,Richard A. Dixon,Zeng-Yu Wang +11 more
TL;DR: It is shown here that genetic modification of switchgrass can produce phenotypically normal plants that have reduced thermal-chemical, enzymatic, and microbial recalcitrance, which has the potential to lower processing costs for biomass fermentation-derived fuels and chemicals significantly.
References
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Journal ArticleDOI
Hydrolysis of lignocellulosic materials for ethanol production: a review.
Ye Sun,Jiayang Cheng +1 more
TL;DR: Simultaneous saccharification and fermentation effectively removes glucose, which is an inhibitor to cellulase activity, thus increasing the yield and rate of cellulose hydrolysis, thereby increasing the cost of ethanol production from lignocellulosic materials.
Journal ArticleDOI
Fermentation of lignocellulosic hydrolysates. II: inhibitors and mechanisms of inhibition.
TL;DR: In this article, the authors discuss the generation of inhibitors during degradation of lignocellulosic materials, and the effect of these on fermentation yield and productivity, and their interaction effects are reviewed.
Book
Lignins. Occurrence, Formation, Structure and Reactions
TL;DR: In this paper, a treatise on lignin sifts and knowledge accumulated from over a century of thought on nature's most enigmatic polymer and presents a workable, logical text.
Journal ArticleDOI
Fermentation of lignocellulosic hydrolysates. I: inhibition and detoxification
TL;DR: In this article, the effect of various detoxification methods on the fermentability and chemical composition of lignocellulosic hydrolysates is discussed. But, the main focus of this paper is on the effects of different batch, fed-batch, and continuous fermentation strategies in relation to inhibition of fermentation.
Journal ArticleDOI
A review of the production of ethanol from softwood
Mats Galbe,Guido Zacchi +1 more
TL;DR: The current status of the technology for ethanol production from softwood is reviewed, with focus on hemicellulose and cellulose hydrolysis, which is the major problem in the overall process.