中文摘要：

磷脂酶C（PLC）能够水解细胞膜主要成分磷脂,使细胞膜通透性增强,从而能够释放出胞内物质。作者构建了PLC与天然胞内定位蛋白葡萄糖异构酶（GI）共表达的重组大肠杆菌,摇瓶发酵胞外上清液中GIC酶活达到3.4 U/mL,占胞外和胞内总酶活的93%,表明GIC成功实现了胞外表达。将胞外上清液中的GIC进行分离纯化和酶学定性,发现其比活为12.1 U/mg,最适反应温度为80℃,最适pH为10,均与对照菌单独表达的GIO性质基本一致。在此基础上,对上述重组菌进行3 L发酵罐培养,发酵周期为24 h,酶活达到17.7 U/mL,表明其良好的工业化放大生产前景。

英文摘要：

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 andcharacterized.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.