短小芽孢杆菌碱性蛋白酶基因在枯草芽孢杆菌WB600中的表达

将来源于枯草芽孢杆菌WB600的启动子PyxiE与碱性蛋白酶基因进行融合，将融合片段插入到大肠杆菌-枯草芽孢杆菌穿梭载体pSUGV4中，构建了表达质粒pSUPyAp. 将该质粒转入枯草芽孢杆菌WB600中，得到转化子pSUPyAp/WB600，它在启动子PyxiE驱动下，能够在牛奶平板上产生透明的水解圈，其发酵上清液中的碱性蛋白酶活性最高为518.5 U/mL，其酶活分别是在启动子Bp53和P43驱动下的3.01倍和1.22倍.

Expression of alkaline protease gene of Bacillus pumilus in Bacillus subtilis WB600

The promoter PyxiE sequence cloned from Bacillus subtilis WB600 and alkaline protease gene of Bacillus pumilus were fused, and then the fused gene was inserted into the shuttle vector pSUGV4 to construct recombinant expression plasmid pSUPyAp. The plasmid pSUPyAp was transformed into B. subtilis WB600 and the transformant pSUPyAp/WB600 displayed the hydrolyzed zone on milk plate. The maximal alkaline protease activity of the transformant under the optimal fermentation conditions was 518.5 U/mL, which is 3.01-fold and 1.22-fold of the same alkaline protease gene under the control of promoter Bp53 and P43, respectively.