2010-01-012024-05-17https://scholars.lib.ntu.edu.tw/handle/123456789/670273摘要：面臨化石能源枯竭、全球暖化加劇等問題，由木質纖維素（lignocellulose）產製生質酒精為目前發展的趨勢，其中又以利用稻桿、蔗渣等農業廢棄物產製生質酒精最符合經濟效益。以木質纖維素產製生質酒精的過程中，經預處理的原料需進一步利用酵素進行糖化，方能進行酒精發酵。採用之酵素主要包括內聚葡萄糖&#37238;（endoglucanase）、外聚葡萄糖&#37238;（exoglucanase）、葡萄糖&#33527;&#37238;（glucosidase）等纖維分解酵素。近年纖維分解酵素之價格雖已降低，但仍為生質酒精生產成本的主要費用。因此，發展單一微生物以進行酵素生產、酵素水解及酒精發酵等所有反應才能將生質酒精的生產成本降至最低。凝集素（agglutinin）為啤酒酵母菌（Saccharomyces cerevisiae）不同交配型（mating type）細胞進行有性吸附（sexual adhesion）所必須的一種細胞表面蛋白質，其蛋白質具有錨碇序列（anchor sequence），故能將蛋白質固定於細胞表面。本研究即計畫將瘤胃微生物之纖維分解酵素基因接合於啤酒酵母菌之凝集素基因，再以啤酒酵母菌進行此融合蛋白質（fusion protein）的表達。確認纖維分解酵素已固定於基因重組酵母菌的細胞表面後，將進一步並評估基因重組酵母菌之纖維分解能力及其應用於聯合生物加工法（consolidated bioprocessing；CBP）之可行性。<br> Abstract: Bioconversion of lignocellulosic feedstocks to fuel-grade ethanol is a promising route towards reduced dependence on fossil fuels and the mitigation of greenhouse gas production. Feedstocks currently under consideration include agricultural residues, such as rice straw and bagasse. Typical bioconversion schemes involve a pretreatment step to improve substrate accessibility, followed by enzymatic hydrolysis of the cellulose component to produce glucose for fermentation. Efficient hydrolysis of cellulose requires the synergistic activities of three types of cellulase enzymes: endoglucanase, exoglucanase, and β-glucosidase. Although the cost of commercial cellulase preparations has been reduced significantly in recent years, enzyme costs are still an obstacle to full-scale process commercialization. Therefore, one-step conversion of cellulose to ethanol with an organism capable of cellulose degradation and efficient fermentation would greatly enhance cost effectiveness of bioethanol production. The native agglutinins are believed to act as adhesion molecules to stabilize cell-cell interactions during mating and to facilitate fusion between the a and α haploid yeast cells. Agglutinin has a anchor attachment signal, which is engaged in anchoring of cell wall protein. In this study, the rumen microbial cellulase genes will be also cloned and fused with the agglutinin gene and expressed in Saccharomyces cerevisiae. The display of cellulase and xylanase proteins on the cell surface of S. cerevisiae will be confirmed. The potential of the recombinant strains to degrade cellulose and be used for consolidated bioprocessing (CBP) will also be evaluated.瘤胃微生物纖維素&#37238細胞表面展現聯合生物加工法Rumen microbecellulasecell surface displayconsolidated bioprocessing