Abstract:β-amylase (AmyM) is an important industrial enzyme, which is mainly used in beer brewing and sugar industry. In this study, AmyM was first amplified from Bacillus megaterium DSM 319, and its expression in B. subtilis ATCC 6051△10 was analyzed. First, recombinant strains were successfully obtained using different single and dual promoters, and they were then cultured in shaking flasks. AmyM synthesized under the control of the P43-P43 dual promoter showed the maximum enzymatic activity (approximately 2950.76 U/mL) after 27 h culture. Subsequently, the impact of carbon catabolite repression on the expression of recombinant AmyM was examined. Results showed that site-directed mutagenesis of bases at sites controlled by catabolite control protein A could effectively alleviate carbon repression, increasing the enzymatic activity of AmyM up to 4663.03 U/mL. Finally, recombinant AmyM was used for glycation, where a maximum maltose conversion rate of 57.62% was achieved. In summary, this study provided a high-efficiency expression scheme for AmyM in B. subtilis and supported the production of recombinant AmyM for industrial applications.
