水/有机溶剂双相体系中色氨酸合成酶酶法合成L-色氨酸  

Enzymatic Synthesis of L-Tryptophan Catalyzed by Tryptophan Synthase in a Water/Organic Solvent Biphase System

作　　者：徐礼生[1] 刘均忠[1] 王治元[1] 张宏娟[1] 刘伟[1] 刘茜[1] 焦庆才[1] 

机构地区：[1]南京大学生命科学学院,医药生物技术国家重点实验室,江苏南京210093

出　　处：《催化学报》2011年第8期1405-1410,共6页

基　　金：国家技术创新基金(02CJ-13-01-16)~~

摘　　要：在水/有机溶剂双相体系中,利用重组大肠杆菌DM206[pET28a-trpBA/BL21(DE3)]色氨酸合成酶催化L-丝氨酸和吲哚合成了L-色氨酸.考察了有机溶剂、有机相乙酸乙酯体积分数、反应温度、水相pH、底物L-丝氨酸与吲哚摩尔比、底物L-丝氨酸浓度、表面活性剂和酶添加量对色氨酸合成酶酶活的影响.结果表明,酶法最佳转化条件为:有机相溶剂为乙酸乙酯,乙酸乙酯的体积分数为2.5%,反应温度为35oC,水相pH值为8,底物L-丝氨酸与吲哚的摩尔比为1:1.2,底物L-丝氨酸浓度为100mmol/L,吐温80的质量分数为0.4%,反应介质中酶的添加量为20g/L.在此条件下酶促反应2.5h,L-丝氨酸转化率可达95%.Enzymatic synthesis of L-tryptophan from L-serine and indole catalyzed by tryptophan synthase from recombinant Escherichia coli DM206 [pET28a-trpBA/BL21（DE3）] in an aqueous/organic biphasic system was carried out.The effects of organic solvents,volume fraction of ethyl acetate,reaction temperature,pH value of the aqueous phase,molar ratio of L-serine to indole,L-serine concentration,sur-factants,and enzyme amount were investigated.Ethyl acetate was found to be the best organic solvent for the reaction.The optimal volume fraction of ethyl acetate was 2.5%.The optimal temperature and pH value were 35 oC and 8,respectively.The optimal molar ratio of L-serine to indole was 1：1.2.The optimal L-serine concentration was 100 mmol/L.The optimal mass fraction of Tween 80 was 0.4%.The optimal enzyme amount was 20 g/L.Under the optimal conditions,bioconversion rate of L-serine reached 95% after 2.5 h in the aqueous/organic biphasic system.

关 键 词：色氨酸合成酶 L-色氨酸 L-丝氨酸 吲哚 乙酸乙酯 水 

分 类 号：TQ922.9[轻工技术与工程—发酵工程]