Production of a new non-specific nuclease fromYersinia enterocoliticasubsp.palearctica: optimization of induction conditions using response surface methodology

A new non-specific nuclease from Yersinia enterocolitica subsp. palearctica (Y. NSN) was expressed in Escherichia coli (E. coli) BL 21 StarTM (DE3)plysS. Induction conditions, including isopropyl-β-D-thiogalactoside (IPTG) concentration, cell density (OD600), induction time and induction temperature, were optimized using response surface methodology. Statistical analysis of the results revealed that induction temperature and all the quadratic terms of variables had significant effects on enzyme activity of Y. NSN. The optimal induction conditions were as follows: 1.5 mmol/L IPTG, OD600 of 0.80, induction time of 20.5 h, and induction temperature of 32 °C. Under the optimized conditions, the highest enzyme activity could be obtained.