Effect Of Surfactants On The β-Glycosidase Enzymatic Synthesis Of Salidroside

The research on glycosides components have been a hot topic in the field of medicinal chemistry as their high physiology and pharmacology activities for a long time. Salidroside is the main active component of the Rhodiola plant and it is known to have antifatigue, anti-aging and anti-radiation activities. At present, the salidrosides which were used to pharmacology research were extracted from raw plant. However, the yields from the natural plant were too low to meet the demands of market. So, it’s essential to develope efficient synthesized technologies to supply the market demands. The new methods of synthesize salidrosides contain chemical synthesis, callus culture means, biocatalysis and so on. To biocatalysis, enzymatic synthesis generally provides higher stereo-and regioselectivity, simpler operation steps and milder reaction conditions. In past years, reaction mediums project from traditional aqueous conditions to a mixture of water and organic solvents, as well as ionic liquids have all been investigated extensively as solutions for enzymatic reactions. In addition, to maintain enzymatic activity in solvents and improve enzymatic recovery immobilization techniques have also been employed, often providing increases in yields.The effects of surfactants on enzymatic activity have primarily focused on lipases, phospholipases, integral membrane enzymes and celluloses. In their studies, some excellent properties of surfactants intervened enzyme were exhibited, such as surfactants helped enzyme to maintain activity, etc. It’s seldom looked up the surfactants were introduced into glucosidase catalytic reaction. Therefore, the pure aqueous phase and aqueous-organic system were established to investigate the influences of surfactants on-glycosidase. Moreover, in view of that tween20was excellent to maintain enzyme activity, it was chose to prepared the tween20-enzyme complex, and this complex’s activity was detected in aqueous-organic single phase.According to the research, in aqueous phase, Tween20was found to be the most effective at maintaining enzyme activity and stability. The residual enzyme activity was at79.7%after6days at50℃in the presence of10g/L of Tween20. Tyrosol also positively influenced the maintenance of enzyme stability. SDS acted cooperatively in the presence of tyrosol to protect the enzyme from inactivation. Compared with the use of surfactant alone, the conversion of glucose was found to decrease after a mixed surfactant solution was employed.In aqueous-n-hexane biphasic systems, SDS was found to be the most effective at maintaining enzymatic activity. The conversion of glucose was enhanced to11.6%by adding0.75g/L SDS in the reaction system. Glucose conversion of11%was achieved by adding CTAB of1.25g/L and tween20of1.75g/L, respectively. For the SDS treatment, a substrate conversion rate of22.3%was obtained under the condition of water content of10%in the biphasic systems.A lipopeptide-biosurfactant was isolated from the cultured of Bacillus subtilis. The enzymatic stability was maintained by the biosurfactant within a period of time. However, the enzyme inactivation began to accelerate as the extension of time.13.7%conversion of glucose was obtained in the presence of2.5g/L of biosurfactant.The tween20-enzyme complex exhibited the function of maintained the enzymatic activity in water-acetonitrile single phase, and the lower the water content of the single system, the more obviously this effect was.