Co-Expression of Phospholipase C and Glucose Isomerase Which Promoting the Extracellular Expression of Glucose Isomerase in E.coli

Abstract:

Phospholipase C（PLC） hydrolyzes the phospholipids in the membrane. The hydrolysis was partial，which would enhance the cell membrane permeability，and then proteins in the cytoplasm were released into culture medium. In this study，PLC was co-expressed with glucose isomerase （GI）. In shake flask fermentation of recombinant E. coli BL21 （DE3），the activity of GIC in culture supernatant was 3.4 U/mL，which was 93% of the total enzyme activity in culture supernatant and cytoplasm. GIC was released into culture medium. The GIC was purified and characterized. The specific activity of GIC was 12.1 U/mg，the optimum temperature was 80 ℃，and the activity of GIC was maximal at pH 10. The characteristics of GIC were similar to GIO，In addition，The enzyme activity reached 17.7 U/mL in 24 hours by utilizing fed-batch strategy in 3 L fermentor.