Combinatorial Induction of Recombinant Dextransucrase Expression in E. coli by IPTG and Lactose

In order to explore the combinatorial induction of recombinant dextransurase experssion in E. coli by isopropyl β-D-1-thiogalactopyranoside(IPTG) and lactose, a mixture of IPTG and lactose was added to the cell culture to induce the expression of recombinant dextransurase. Based on the optimal culture medium, IPTG concentration and the amount of lactose added, bacteria concentration and induction time revealed significant impacts on the enzyme activity. The results showed that the optimal concentrations of IPTG and lactose were 0.1 mmol/L and 2.5 g/L, respectively, and optimal induction time was 4 h at 25 ℃. Under these culture conditions, the activity of dextransucrase could reach up to 40.44 U/mL. The combinatorial induction of recombinant E. coli dextransurase by IPTG and lactose was feasible, greatly reducing the dosage of IPTG and industrial production costs.