酶催化直接糖基化制备p-羟基苯乙基β-D-葡萄糖苷

Preparation of p-Hydroxyl Phenylethanolβ-D-Glucoside byβ-Glucosidase Catalyzed Direct Glucosylation

研究了水-有机溶剂体系中β-葡萄糖苷酶催化直接糖基化反应制备p-羟基苯乙基β-D-葡萄糖苷,考察了反应体系、水分活度(a_w)、反应温度和β-D-葡萄糖与p-羟基苯乙醇摩尔比对酶稳定性及产率的影响。实验结果表明,在水-乙腈、水-1,4-二氧六环和水-1,2-二乙酰氧基乙烷体系中均可进行直接糖基化反应。在水-1,2-二乙酰氧基乙烷体系中,合适的反应条件为p-羟基苯乙醇0.6 mol/L,β-D-葡萄糖0.2 mol/L,酶量3.6 mg/10 mL,a_w为0.76,52℃,pH值6.2,280 r/min,反应26 h后产率达到20.66%。随反应时间增加,产物抑制和酶稳定性降低程度明显增加,限制了产率的提高。

The conditions for the preparation of p-hydroxyl phenylethanol β-D-glucoside by β-glucosidase catalyzed direct glucosylation in aqueous-organic systems were investigated. The results showed that aqueous-acetonitrile, aqueous-1, 4-dioxane and aqueous-1,2-diacetoxyethane were suitable for the reaction. The αw of the system, β-D-glucose concentration and molar ratio of p-hydroxyl phenylethanol to β-D-glucose had obvious influence on the yield of direct glucosylation. Under the conditions of β-D-glucose0. 2 mol/L, molar ratio of p-hydroxyl phenylethanol to β-D-glucose 3, enzyme loading 3.6 mg/10 mL, αw 0.76, 52 ℃, pH6.2 and 280 r/min, 20.66% yield was obtained in aqueous-1, 2-diacetoxyethane after 26 h reaction. The effect of product inhibition and enzyme deactivation decreased evidently and limited the increase of the yield with reaction continuing.