【摘要】 为了实现利用生物酶转化法生产D 对羟基苯甘氨酸 ,以工程菌E .coliBL2 1 pMD T7 dht细胞作酶源 ,对底物对羟基苯海因到中间体N 氨基甲酰 D 对羟基苯甘氨酸的酶转化条件进行了优化 .酶转化的最适温度为 37℃ ,最适pH为 9 0 .在Tris HCl、磷酸盐、碳酸盐和硼酸盐 4种缓冲体系中 ,底物对羟基苯海因的转化率相近 .菌体细胞经适当冻融后 ,底物对羟基苯海因的转化率被提高 .水溶性有机溶剂DMSF、DMF和Tween 80使对羟基苯海因的转化率降低 .转化时底物和菌体的合适比例为 30g L对羟基苯海因和 10g L湿菌体 .经工程菌E .coliBL2 1 pMD T7 dht细胞催化 ,底物的转化率在 13h内可达到 96 % .所制备的产物熔点、旋光性和红外光谱等与标准品一致更多还原

【Abstract】 The enzymatic conversion of substrate D,L-p-Hydroxyphenylhydantoin (D,L-p-HPH) to N-carbamoyl-D-p-hydroxyphenylglycine (CpHPG) were carried out using D-hydantoinase genetic engineering strain E.coli BL21/pMD-T 7-dht resting cells with the aim of the industrial enzymatic production of D-p-hydroxyphenylglycine (D-p-HPG). Optimization studies for the bioconversion were performed to increase the yield of product CpHPG. The experiment results showed that the optimal pH and temperature of CpHPG production were 9.0 and 37℃, respectively. The conversion yields of D, L-p-HPH to CpHPG were identical almost in different buffer system (pH 9.0) including Tris-HCl buffer, phosphate buffer, borate buffer and sodium carbonate buffer. After the strain cells were freeze-thawed appropriately, the conversion yield could be increased. The conversion yield of D, L-p-HPH to CpHPG by D-hydantoinase was decreased in presence of the water-miscible organic solvents, DMSF, DMF and Tween-80. The suitable ratio of substrate concentration and bacterial weight was 30 g/L D, L-p-HPH and 10 g/L intact cell (wet weight). The conversion yield of D,L-p-HPH to CpHPG catalyzed by the genetic engineering strain E .coli BL21/pMD-T 7-dht resting cells could reach 96% within 13 hours. The melting point, optical rotation and infrared absorption spectrum of product were identical with the control product of CpHPG.更多还原