ABSTRACT
The aim was to develop the simple preparation method of mogroside ⅢE,and to lay the foundation for the development of the mogroside sweeteners. In the present study,the glycosidase CPU-GH17,which can regio-selectively biosynthesize mogroside ⅢE from mogroside V,was screened from the established library of glycosi-dases. Then,the soluble expression condition of CPU-GH17 in E. coli was exploited by investigating isopropyl β-D-thiogalactoside (IPTG)concentration,culture temperature and induction time,and 0. 4 mmol/L IPTG,15 °C and 12 h was used as optimal condition. The result showed that mogroside V could be completely converted into mogroside ⅢE under the conditions of pH 6. 0,45 °C,3 U/mL enzyme loading,5 mg/mL substrate concentration for 20 h. In conclusion,a biosynthetic system for the regio-selective preparation of mogroside ⅢE by recombinant CPU-GH17 was successfully established and verified at a preparative scale.