中文摘要：

PCR扩增里氏木霉（Trichoderma reesei）2个α-半乳糖苷酶基因agl2和agl3，将其分别与表达载体pY—ES2连接，电转化酿酒酵母（Saccharomyces cerevisiae）INVSc1菌株。从重组菌株提取载体进行单酶切凝胶电泳检测，证实agl2和agl3分别在重组菌株AGL2和AGL3表达。以葡萄糖和棉子糖为碳源培养菌株，2株重组菌的生长速率均显著高于原始菌株，提前8h菌数达到最大，其中以AGL3的生长速率提高较为明显，重组还使菌株在液体培养基由原来的部分絮凝转变为完全游离状。2株重组菌株均不能利用蜜二糖为碳源生长。

英文摘要：

Two α-galactosidase genes agl2 and agla, amplified respectively by PCR from the ge- nomic DNA of Trichoderma reesei , were respectively electric transformed the S. cerevisiae strain INVScl using expression vector pYES2. The agl2 and agl3 were verified to be expressed respectively in the recombinant AGL2 and AGL3 by agarose electrophoresis analysis of the BamHI enzymatic digesting products of expression vectors isolated from recombinants. Cultiva- tion in the medium with glucose or raffinose as carbon resource, the growth of both recombinants was significantly faster than that of INVScl strain, the maximum cell number was occurred 8 hours earlier than INVScl,and the cell distribution in media was changed from some extent flocculation of INVScl to the complete free status of both recombinants. However,the result was difference with the previous investigation, neither recombinants nor INVScl could grow in the medium with melibiose as carbon resource. The results imply that the growth of industrial S. cerevisiae strain can be enhanced to facilitate the ethanol fermentation by transformation of α-galactosidase genes from T. reesei . Since no any relationship between a galactosidase gene and microbial growth or cell flocculation was reported previously,the mechanism of the results should he addressed future