Monday, April 30, 2007

Simultaneous saccharification and fermentation of wheat straw using recombinant Saccharomyces cerevisiae TMB3400

Kim Olofsson, Andreas Rudolf, and Gunnar Lidén. Department of Chemical Engineering, Lund University, Getingevägen 60, S-221 00, Lund, Sweden

Wheat straw is an abundant agricultural residue in several parts of Europe which can be used as a raw material for bioethanol production. Due to the high xylan content in wheat straw fermentation of xylose to ethanol is crucial to meet desired overall yields of ethanol. In the present work a recombinant xylose fermenting yeast, Saccharomyces cerevisiae TMB3400 (Wahlbom et al. (2003) FEMS Yeast Res 3:319-326), cultivated aerobically on wheat straw hydrolysate, was used to perform simultaneous saccharification and fermentation (SSF) of steam pretreated wheat straw. The influence of fermentation temperature and fermentation strategy was studied in relation to xylose consumption, ethanol formation and by-product formation. Using a fed-batch strategy xylose fermentation significantly contributed to ethanol yields reaching 80% of the theoretical value based on available sugars. The results show that this process option may indeed be a viable choice for efficient ethanol production from wheat straw.