Display of Serratia marcesens lipase on surface of Escherichia coli using N-terminal domain of ice nucleation protein
利用冰核蛋白N末端结构域在大肠杆菌表面展示粘质沙雷氏菌脂肪酶

Objective] We constructed an Escherichia coli strain displaying an active lipase on the cell surface by cell surface engineering and characterized the displayed lipase.Methods] Es-cherichia coli surface display vector of lipase was constructed by fusing sequence encoding the N-terminal domain of ice nucleation protein with Serratia marcesens lipase gene,and the re-combinant vector was transformed into Escherichia coli BL21(DE3).Results] The highest lipase activity was observed when the recombinant cells were induced with 0.05 mmol/L iso-propy-β-D-thiogalactoside(IPTG) and cultured at 25 °C for 16 h.Optimal pH and optimal temperature for cell surface-displayed lipase was 9.0 and 40 °C,respectively.The thermal stability of surface-displayed lipase was improved compared with that of free lipase,and the residual activity was above 90 percent of initial activity after incubated at 40 °C for 1 h.Conclusion] The above results suggest that the bacterial surface display technology offers a promising alternative approach for immobilization of lipases.