Immobilized Substrate Catalytic Synthesis Of Alpha Arbutin

In the field of the whitening research arbutin heat rises in recent years with its unique and effective whitening effect, high stability in the cosmetics,hard to produce of harmLy substances, and many other advantages.The synthesis of alpha arbutin is given priority to with biological methods, in this way, product composition is pure and the operation is simple,economic. Biological methods with hydroquinone as the substrate, transfer glycosidic enzyme catalytic reaction produce alpha arbutin, substrates has inhibitory effect on bacteria, in reaction system.In this study, a-arbutin was synthesized by substrate immobilized fermentation on the basis of free fermentation. The inhibitory effect of substrate on the concentration of the substrate in the reaction system was reduced and the concentration of the product was increased.The main contents of the experiment include three parts: In the first part,the appropriate carrier is screened for substrate immobilization optimized the substrate adsorption and product desorption conditions The results showed that NKA- II resin has better adsorption for hydroquinone. Optimal conditions was that in the temperature 20?, the adsorption time of the substrate hydroquinone was 50 min, and the adsorption time of the product a-arbutin was 200 min. The best desorption conditions: desorption temperature is 22?,desorption volume ratio is 70%, 1.0 g resin corresponding to 25 mL desorption solution.In the second part, the immobilized resin is added to shake flask for fermentation and then carry out the amplification reaction of 5 L fermenterThe optimum reaction conditions were as follows: Temperature 24?,time 110h, substrate concentration 90 g·L-1 (resin adsorption capacity is 80 mg·g-1) OD660 0.422, in this condition a-arbutin concentration up to 18.5 g·L-1.The optimum reaction conditions in the 5L fermenter were as follows:temperature 24 ?, time 84 h, substrate concentration 130 g·L-1 , in this condition a-arbutin concentration up to 27.5 g·L-1. The yield of a-arbutin increased by 48.6 % compared to shake flask fermentation.The third part, according to the chemical and physical properties of the substrate, synthesis the resin that has high performance adsorption, And characterized the structure of the synthetic resin.The ratio of monomer to porogen is 1:1.5, The proportion of good porogen to non-porogen is 10:20 ; Stirring speed is 300 rpm; The chloromethylation temperature is 80?; The chloromethylation time is 12 h;The chloromethylation volume is 50 mL; The reaction time was 16 h used nitrobenzene as post-crosslinking solvent, in this condition the adsorption of resin up to 79 mg·L-1. The specific surface area of the resin is 942 m2·g-1, the average pore size is 34 nm.