Optimization of Cold-adapted α-amylase Production in Escherichia coli by Regulation of Induction Conditions and Supplement with Osmolytes

Abstract

In this study, the induction expression conditions of cold-adapted α-amylase (Amy175) from Pseudoalteromonas sp. M175 in E. coli were investigated. The optimal induction conditions were as follows: 20 mM L-proline was added into the culture medium at the initial inoculation time point, the concentration of the inducer IPTG was 0.04 mM, the induction point was 0.6 of OD600, the induction temperature was 15 °C, and the induction time was 12 h, and the rotation speed was 120 rpm. The maximum amylase activity could reach 141.1 U/ml at the optimal induction conditions. Thus, the yield of the active and soluble α-amylase was found to be increased in the lower induction temperature, lower IPTG concentration, and the supplement of the proper amount of L-proline into the culture medium.