Construction of an inducible expression vector based on α-galactosidase gene as a selection marker for Saccharomyces cerevisiae and its application

ZHANG Wei1,GUO Qin2,RUAN Hui3,HE Guo-qing3(1.School of Basic Medical Science,Wenzhou Medical College,Wenzhou,Zhejiang 325035,China;2.School of Food and Biological Engineering,Jiangsu University,Zhenjiang,Jiangsu 212013,China;3.School of Biosystems Engineering and Food Science,Zhejiang University,Hangzhou 310058,China)

α-galactosidase gene;selection marker;Saccharomyces cerevisiae;β-1,3-1,4-glucanase

YGM-α-gal,an expression vector for Saccharomyces cerevisiae,was constructed containing α-galactosidase gene as selection marker and an inducible GAL1 promoter.The β-1,3-1,4-glucanase gene cloned from Bacillus subtilis was inserted into the multiple cloning sites of the plasmid YGM-α-gal to generate YGMPA-α-gal,then to transform the host yeast,and β-1,3-1,4-glucanase was efficiently expressed as a secretive protein in S.cerevisiae.The results indicated that the β-1,3-1,4-glucanase activity in the ferment liquid in shake flask was about 411.9 U·mL-1 after adding 2% galactose for 24 h,and the α-galactosidase activity reached 64.2 U·mL-1 after adding 2% galactose for 60 h.So the α-galactosidase gene can be used as an effective selection marker for screening the positive transformants of food-grade yeast expression system.