Fermentation of steam-exploded corn stover hydrolysate and its distillation residue by Pichia stipitis.

In order to utilize sugars in lignocellulosic hydrolysate efficiently,a novel technology was applied in present study.The glucose in the corn stover hydrolysate was converted to ethanol by Saccharomyces cerevisiae and the ethanol in the fermentation broth was removed by distillation.Then the xylose in the distillation residue was fermented to produce ethanol by an adapted Pichia stipitis.The results showed that the ethanol yield and xylose consumption ratio of 84.4 g/L xylose fermentation in the distilled hydrolysate were 80.4% and 89.7%,respectively,after 48 h fermentation.The utilization of xylose in distillation residue with higher inhibitor concentration could be improved by higher initial pH.The ethanol yield and xylose consumption ratio were 80.2%(76.3%) and 94.8%(91.0%),respectively,when the initial pH was 5.5 and the acetic acid in the distillation residue was 3.2 g/L.This fully indiacted that xylose in S.cerevisiae culture broth can be effectively utilized by adapted P.stipitis by using this novel technological route.This novel method solved the problem of xylose utilization efficaciously in the process of ethanol production from lignocellulosic materials.