Astragaloside Transformation By The Enzyme From Mold Strain

To obtain the more Astragaloside Ⅳ, the method to prepare Astragalosides was studide and the enzyme from mold strain was used to hydrolyze the3-O-three-glycoses-astragaloside to Astragaloside IV. The paper mainly focused on Astragalosides isolated according to the content of the3-O-three-glycoses-astragaloside, and purification and characters of astragaloside glycosidase from microorganism sp.0#by filtrated.The paper selected ethanol and n-butanol extracting technology to prepare Astragalosides from Astragalus so that the loss of3-O-three-glycoses-astragaloside was low. The content of Astragalosides was4.0g with4.0%of yield, and the yield of3-O-three-glycoses-astragaloside was about25%.sp.00#was selected from sp.00#, sp.39#, sp.48#, sp.42#as a sample. It confirmed that sp.00#was the best strain. Furthermore it was shown that96hours was the best period of enzyme fermentation. The enzyme from sp.00#had the activity to hydrolyze3-O-three-glycoses-astragaloside into Astragaloside Ⅳ. The methods was studied to detect enzyme activity. The enzyme was purified by DEAE-cellulose DE52and the astragaloside glycosidase was eluted under120mmol/L KC1. The pure enzyme showed a single protein band, and the protein molecular weight was estimated to be about47kDa by SDS-PAGE.Also the properties of the astragaloside glycosidase were studied. The enzyme optimal temperature was30℃, the optimal pH was5.0, the optimal reaction time was24h, and the optimal substrate concentration was20mg/mL.The content of the products of enzyme reaction was17.27g with107.9%of yield. The pure Astragaloside IV could be obtained when the products were purified by silica gel column elution with the solvent of chloroform and methanol at the rate of8.2:1.8. The content of Astragaloside Ⅳ after biotransformation has increased to be7.54%, and it was identified by HPLC with the purification of about80%.