【摘要】 将淀粉酶基因引入酿酒酵母构建能直接利用淀粉的酵母菌种在酿造和酒精生产中有重要的商业价值。本研究利用酵母MFα因子的启动子、信号序列和地衣杆菌α-淀粉酶基因的转录终止信号构建酵母的分泌型表达载体YEpMT25并将黑曲霉葡萄糖淀粉酶的cDNA插入YEpMT25,组建含cDNA的重组质粒YEpMTG36,经调整信号序列和cDNA之间的读码框架后转化酿酒酵母GRF18,酶活性测定证明葡萄糖淀粉酶cDNA已经表达并能向胞外分泌酶活力。更多还原

【Abstract】 Construction of yeast that can directly utilize starch by introducing amylolytic enzyme genes into Saccharomyces cerevisiae is of great commercial importance in brewing industry and ethanol production. This report describes the construction of secretive expression vector and the expression of cDNA encoding the A.niger glucoamylase in Saccharomyces cerecisiae. The secretion vector YEpMT25 was constructed by inserting the promoter and signal sequence of yeast MFα gene and the terminator of α-amylase gene from B.licheniformis into the E.coli-yeast shuttle plasmid YEplac 181. The glucoamylase GAI cDNA of A.niger was ligated to the plasmid YEpMT25. The resultant plasmid YEpMTG36, after readjusting the reading, frame between the signal sequence and the cDNA, was introduced into S.cerevisiae GRF18. Yeast cells transformed with the recombinant plasmid synthesize and secrete active glucoamylase into the culture medium.更多还原