Construction and Expression of Gene Engineering Bacterium of α-amylase in Recombinant Bacillus subtilis

According to α-amylase gene sequence from Bacillus subtilis published in GenBank,primers were designed.Gene sequence(amy) was obtained by PCR method.The cloned sequence was inserted into the E.coli-Bacillus subtilis shuttle expression vector pP43C to construct recombinant plasimd: pP43Camy.Then,recombinant plasmids was transferred into eight proteases deficient host WB800,and the engineering strains with high expression level: Bacillus subtilis WB800/pP43Camy was obtained by screening.The enzyme activity of Engineering strain reached 960U by flask fermentation.Optimum temperature and optimum pH of the recombinant α-amylase were respectively 70 ℃ and 6.0.It has a good potential for application.