Heterologous gshF gene expression in various vector systems in Escherichia coli for enhanced glutathione production
2015
Wang, Cheng | Zhang, Jing | Wu, Hui | Li, Zhimin | Ye, Qin
Glutathione (GSH), an important bioactive product, is widely used in production of pharmaceuticals and foods. In this study, four different vector systems, pET28a, pUC18, pUC19-P32, and pUC19-Pabb, were applied for expression of gshF, encoding the bifunctional glutathione synthetase of Streptococcus thermophiles. These four constructs were named as pET28a-gshF, pUC18-gshF, pUC19-P32-gshF and pUC19-Pabb-gshF, respectively, and then introduced into Escherichia coli strain BL21(DE3) for further investigation of protein expression and GSH production. The expression levels of the GshF in BL21(pUC19-P32-gshF) and BL21(pUC19-Pabb-gshF) were much lower than those of BL21(pET28a-gshF) and BL21(pUC18-gshF). In the fed-batch fermentation, the GSH accumulated by BL21(pUC18-gshF) reached 15.21g/L, which was the highest level of GSH biosynthesis ever reported. Although BL21(pUC19-Pabb-gshF) produced less GSH compared to BL21(pUC18-gshF), the final GSH concentration produced by BL21 (pUC19-Pabb-gshF) still accumulated to 5.09g/L, which indicated the potential application of the constitutive promoter in GSH production.
显示更多 [+] 显示较少 [-]