Hydrolyzing Dioscin To Diosgenin By Enzyme From Mold

In this paper, three methods were used to study the hydrolysis of dioscin to diosgenin. A new dioscin-glycosidase that could hydrolyze milti-glycosides of dioscin {3-O-α-L-(1â†'4)-rha,[3-O-α-L-(1-+2)-rha]-β-D-glc-diosgenin} from sp.42d stain was isolated, purified and characterized, its molecular weight was determined by SDS-polyacrylamide gel electrophoresis, and its properties were analyzed. The reaction product was identified by HPLC.Substrate dioscin was extracted from Chinese traditional medicine herb Dioscorea zingiberensis C.H. Wright, and the yield was3.15%by using ethanol. Besides dioscin a little diosgenin was detected by TLC, the solvent was chloroform:methanol:water=7:3:0.5.Three methods were used to study the hydrolysis of dioscin to diosgenin i.e. fermentation by bacteria, fermentation by fungi and hydrolysis by enzyme. The yield was20%in fermentation by bacteria,30%in fermentation by fungi and81%in hydrolysis by enzyme.The enzyme from sp.42d stain had the dioscin-glycosidase activity hydrolyzing dioscin into diosgenin. The enzyme was purified by DEAE-cellulose DE52, the dioscin-glycosidase was eluted under180mmol/L KC1. And the molecular weight determined by SDS-PAGE was about35kDa.Also the properties of the dioscin-glycosidase were studied. The enzyme optimal temperature was35℃; the optimal pH was5.0; the optimal reaction time was24h; and the optimal substrate concentration was10mg/mL. According to optimal condition fadrication1L substrate concentration, the products is7g.Before analyzing by HPLC, the products of enzyme reaction were purified by AB-8and D-280Diaion resin. The purification of diosgenin was about96.9%.