Increased tolerance and conversion of inhibitors in lignocellulosic hydrolysates by <i>Saccharomyces cerevisiae</i>

TLDR

Hydrolysis of lignocellulosic biomass releases monomeric sugars and a broad range of inhibitors—furans, weak acids, and phenolics—that impair ethanol yield by reducing microbial performance during fermentation. The study aims to overcome inhibitor effects by developing strategies that enhance natural tolerance and employ fermentation control. The authors review inhibitor origins, effects, and mechanisms on *S. cerevisiae*, and discuss fermentation control, metabolic, genetic, and evolutionary engineering approaches to produce tolerant strains. *S.

Abstract

Abstract During hydrolysis of lignocellulosic biomass, monomeric sugars and a broad range of inhibitory compounds are formed and released. These inhibitors, which can be organized around three main groups, furans, weak acids and phenolics, reduce ethanol yield and productivity by affecting the microorganism performance during the fermentation step. Among the microorganisms that have been evaluated for lignocellulosic hydrolysate ethanol fermentation, the yeast Saccharomyces cerevisiae appears to be the least sensitive. In order to overcome the effect of inhibitors, strategies that include improvement of natural tolerance of microorganism and use of fermentation control strategies have been developed. An overview of the origin, effects and mechanisms of action of known inhibitors on S. cerevisiae is given. Fermentation control strategies as well as metabolic, genetic and evolutionary engineering strategies to obtain S. cerevisiae strains with improved tolerance are discussed. Copyright © 2007 Society of Chemical Industry