Expression and Characterization of Recombinant Sucrose Phosphorylase.

SPase is widely used in the food, cosmetics, and pharmaceutical industries. Previously, a SPase gene was cloned from Bifidobacterium longum JCM1217 and constructed into Escherichia coli BL21. In this paper, its expression conditions were optimized. The results showed that several induction factors determined the expression efficiency of SPase. The initial cell density, IPTG concentration, and induction time and temperature significantly (p < 0.01) affected the total protein content and activity of expressed SPase. The highest expression efficiency was obtained at an initial cell density of OD600  = 0.5, with 0.05 mM IPTG, followed by shaking at 180 rpm and incubation at 30 °C for 15 h. The purified SPase had a specific activity of 122.1 U/mg, which was raised by 1.85 -fold more than that before optimization, and its recovery yield was 86%. Furthermore, SPase also showed higher thermostability. The results of this study provide essential information for the industrial production of SPase.