ETHANOL-PRODUCTION FROM CORN COB PRETREATED BY THE AMMONIA STEEPING PROCESS USING GENETICALLY-ENGINEERED YEAST

A new and effective pretreatment process for biomass conversion involv es the steeping of biomass in 2.9 M NH4OH. This resulted in the removi ng about 80-90% of the lignin along with almost all the acetate from c ellulosic residues. Based on dry cellulose from corn cob, a high gluco se yield of 92% was obtained after enzymatic saccharification of cellu lose fraction. By using a genetically engineered, xylose-fermenting Sa ccharomyces 1400(pLNH33) in the batch fermentation of a glucose-xylose mixture from corn cob, an ethanol concentration of 47 g/L was obtaine d within 36 h with 84% yield. In addition, an ethanol concentration of 45 g/L was obtained within 48 h with 86% yield using simultaneous sac charification-fermentation process.