Improving the fermentation performance of Saccharomyces cerevisiae by laccase during ethanol production from steamexploded wheat straw at high substrate loadings

Abstract

Operating the saccharification and fermentation processes at high substrate loadings is a key factor for making ethanol production from lignocellulosic biomass economically profitable. However, increasing the substrate loading presents some disadvantages, among them larger generation of inhibitors, which negatively affect fermentation performance. In this study, laccase enzymatic treatment was evaluated as a method to reduce these inhibitory effects. The laccase efficiency was analyzed in a presaccharification and simultaneous saccharification and fermentation process (PSSF) at different high substrate loadings. Water insoluble fraction (WIS) from steam-exploded wheat straw was used as substrate and Saccharomyces cerevisiae as fermenting organism. Laccase supplementation reduced strongly the phenolics content in the media, without affecting weak acids and furan derivates. It resulted in an improved yeast performance during simultaneous saccharification and fermentation process, increasing significantly ethanol productivity.