The purified D-hydantoinase was immobilized on EAH sepharose 4B via the carbodiimide method with a yield of enzyme activity up to 79.44%.The immobilized hydantoinase showed remarkable stability at 4℃.An integrated pr...The purified D-hydantoinase was immobilized on EAH sepharose 4B via the carbodiimide method with a yield of enzyme activity up to 79.44%.The immobilized hydantoinase showed remarkable stability at 4℃.An integrated process of N-carbamoyl-D-phenylalanine(N-D-Phe)synthesis from D,L-5-benzylhydantoin(D,L-BH)catalyzed by immobilized D-hydantoinase coupled with an ion-exchange unit for in situ product removal(ISPR)was established.The variation of pH and conversion in the fixed-bed reactor with or without ISPR was compared at different temperatures,initial substrate concentrations and volumes of adsorbent.Within 24 h,the pH value in the reactor with ISPR could be kept at the alkaline range,which was beneficial to the enzymatic conversion and racemization of L-5-benzyl hydantoinase.This led to a higher overall conversion of 62.725% under optimal operation conditions,an increase of 89.3% compared with the fixed-bed reactor without ISPR.展开更多
报道了中试规模制备L-茶氨酸和L-谷氨酰胺的一种方法。以廉价的L-谷氨酸为原料,采用邻苯二甲酰基作为保护基,保护L-谷氨酸的α-氨基,醋酐回流10 m in使其分子内脱水生成N-邻苯二甲酰-L-谷氨酸酐,在常温、常压条件下,分别与2 mol/L氨水和...报道了中试规模制备L-茶氨酸和L-谷氨酰胺的一种方法。以廉价的L-谷氨酸为原料,采用邻苯二甲酰基作为保护基,保护L-谷氨酸的α-氨基,醋酐回流10 m in使其分子内脱水生成N-邻苯二甲酰-L-谷氨酸酐,在常温、常压条件下,分别与2 mol/L氨水和2 mol/L乙胺水溶液反应生成中间产物N-邻苯二甲酰-L-谷氨酰胺、N-邻苯二甲酰-L-茶氨酸,中间产物在室温条件下与0.5 mol/L水合肼反应48 h脱除保护基,分别以57%、61%的收率得到L-谷氨酰胺和L-茶氨酸。展开更多
文摘The purified D-hydantoinase was immobilized on EAH sepharose 4B via the carbodiimide method with a yield of enzyme activity up to 79.44%.The immobilized hydantoinase showed remarkable stability at 4℃.An integrated process of N-carbamoyl-D-phenylalanine(N-D-Phe)synthesis from D,L-5-benzylhydantoin(D,L-BH)catalyzed by immobilized D-hydantoinase coupled with an ion-exchange unit for in situ product removal(ISPR)was established.The variation of pH and conversion in the fixed-bed reactor with or without ISPR was compared at different temperatures,initial substrate concentrations and volumes of adsorbent.Within 24 h,the pH value in the reactor with ISPR could be kept at the alkaline range,which was beneficial to the enzymatic conversion and racemization of L-5-benzyl hydantoinase.This led to a higher overall conversion of 62.725% under optimal operation conditions,an increase of 89.3% compared with the fixed-bed reactor without ISPR.
