Ethanol fermentation from cellulose hydrolysate by a recombinant cellooligosaccharide-assimilating yeast

• Main Authors: CHENG-YU LIU, 劉政佑
• Other Authors: Cheng-Kang Lee
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/85620090627801367724

碩士 === 國立臺灣科技大學 === 化學工程系 === 96 === The engineering of cell surface display is immobilization of heterogeneous protein on cell surface . It is widely used in catalytic reaction of cell , adsorbent of cell , vaccine , biosensor .We discuss that we will display �毢eta-glucosidase on yeast surface and use it to produce bioethanol from cellulose.Beta-glucosidase can hydrolyzes cellobiose to glucose that can provide energy for biomass and producing ethanol. 100(g/l) cellobiose as carbon source can obtain 23(g/l) ethanol from Beta-glucosidase-surface displaying yeast , but host can’t produce any ethanol , therefore the technology is opportunity to directly utilize cellulose to produce ethanol by simultaneous saccharification and fermentation (SSF) . Although commercial cellulose from Trichoderma contain endogenous Beta-glucosidase , but the activities of this enzyme are generally insufficient to prevent the accumulation of cellobiose, resulting in product inhibition of endoglucanases and cellobiohydrolases. Therefore we tried genetically to immobilize Beta-glucosidase on the cell surface of the yeast Saccharomyces cerevisiae in its active form to supply this insufficient enzyme , and then successfully promote the efficiency of producing ethanol from cellulose by SSF process .