Expression of Paenibacillus macerans α-cyclodextrin Glycosyltraferase in Bacillus subtilis by Maltose Induction

The α-cgt gene was obtained from Paenibacillus macerans by PCR,and then it was cloned into Escherichia coli-Bacillus subtilis shuttle vector pGJ103 and transformed into B.subtilis WB600.After cultivation for 48 h with shake flask in 1.5% maltose initial medium,the α-CGTase activity of recombinant B.subtilis was 6.1U/ml.In addition,the experiment optimized the culture conditions of the recombinant B.subtilis strain in shaking flask by means of a single factor synthesis and Box-Behnken design(BBD).The analysis predicted the concentrations of maltose,corn starch and yeast extract were at 15 g/L,13 g/L,and 20 g/L,respectively.In this condition,the experimental result of 17.6 U/ml could be obtained when the cells were cultured for 36 h in shaking flasks.The CGTase activity reached 20 U/ml at 30 h of culture in a 5 L bioreactor(hydrolysis activity was 1.4×104 IU/ml).