Ethanol production from acid hydrolysate of wood biomass using the flocculating yeast Saccharomyces cerevisiae strain KF-7

An ethanol production process using the flocculating yeast Saccharomyces cerevisiae strain KF-7 with acid hydrolysate of wood biomass as feed was investigated. Corn steep liquor (CSL) supplemented with KH2PO4, MgSO4, and CaCl2 was used as the source of nitrogen and mineral nutrients. Using a tower-type reactor (working volume (WV), 0.45 L), continuous fermentation with a high ethanol productivity of over 20 g/(L h) was achieved at a dilution rate of 0.3 h(-1) with a pH of 4.5 at 35 degrees C. A continuous fermentation process using two tower-type reactors (WV, 4.5 L each) connected in series was then constructed to decrease the concentration of residual sugars (except for xylose). The contamination of bacteria was effectively repressed and an ethanol productivity of over 12.6 g/(L h) was achieved at an overall dilution rate of 0.2 h(-1) with a pH of 4.0 at 35 degrees C. Strain KF-7 was thus demonstrated to be suitable for the production of ethanol from acid hydrolysate of wood biomass. (0 2005 Published by Elsevier Ltd.