固定化糖基转移酶和蔗糖合酶偶联合成红景天苷

Synthesis of Salidroside by Coupling Immobilized Glycosyltransferase and Sucrose Synthase

摘要:

目的 开发一种利用固定化酶偶联蔗糖合酶合成红景天苷的催化体系。方法 以镍螯合聚丙烯酸树脂为固定化载体，分别固定原核表达的糖基转移酶UGT85AF8和蔗糖合酶GmSUS。其中固定化UGT85AF8催化酪醇发生糖基化反应，固定化GmSUS实现尿苷二磷酸葡萄糖（uridine diphosphate glucose，UDPG）的循环再生。对反应体系的温度、pH、酶添加量和底物浓度等参数进行优化，考察固定化酶的重复使用性能，并采用大孔树脂LSA-30对红景天苷进行分离纯化。结果 在最优条件下反应12 h，红景天苷产量达11.87 g/L。连续6批反应的平均摩尔转化率为88.47%，纯化后的红景天苷纯度>99%，结晶回收率为51.49%。结论 该研究开发的固定化酶偶联合成红景天苷的催化体系具备良好的工业化应用潜力。

Abstract:

Objective This study aimed to develop a catalytic system utilizing immobilized enzyme coupling glycosyltransferase for the synthesis of salidroside. Method The prokaryotically expressed glycosyltransferase UGT85AF8 and sucrose synthase GmSUS were immobilized on nickel-chelated polyacrylic acid resin. The immobilized UGT85AF8 was used to catalyze tyrosol glycosylation, and the immobilized GmSUS was used for the regeneration of uridine diphosphate glucose (UDPG). The reaction system conditions, including temperature, pH, enzyme loading, and substrate concentration, were optimized. The reusability of immobilized enzymes was investigated, and salidroside was separated and purified via the macroporous resin LSA-30. Result Under optimal conditions, the reaction for 12 h achieved a salidroside titer of 11.87 g/L. Moreover, the average molar conversion rate was 88.47% in six consecutive reaction batches. After purification, the purity of salidroside exceeded 99%, with a crystallization recovery rate of 51.49%. Conclusion The immobilized enzyme coupling catalytic system demonstrates promising potential for industrial-scale production of salidroside.