Strategies for producing recombinant sucrose phosphorylase originating from Bifidobacterium longum in Escherichia coli JM109

The optimal production conditions of sucrose phosphorylase (SPase), which catalyzes transferring sugars to polyphenols, cloned from the anaerobic Bifidobacterium longum into Escherichia coli JM109 were studied. Without isopropyl-beta-o-thiogalactopyranoside (IPTG), the segregational stability of the recombinant plasmids was maintained over 80%, even in the absence of antibiotic pressure. When IPTG was added, the plasmids were completely lost after 80 generations. The structural stability of the plasmid was found to be well-maintained. The earlier induction with 10 mu M of IPTG at 37 degrees C was best for the high volumetric activity of the enzyme. The maximal activity of SPase per cell mass was found to be much higher in M9 media than in LB media. In batch bioreactor culture, the maximum values for cell mass concentration, volumetric activity of SPase, and specific activity of SPase based on total soluble protein were 0.84 g l(-1), 2.65 U ml(-1), and 18.14 U mg(-1) of soluble protein, respectively. (C) 2008 Elsevier Ltd. All rights reserved.