重组大肠杆菌高效催化合成L-茶氨酸

High level conversion of L-theanine by recombinant Escherichia coli

利用重组大肠杆菌Rosetta(DE3)/p ET28a-GGT催化L-谷氨酰胺和乙胺盐酸盐生成L-茶氨酸。首先对重组菌的催化反应条件进行优化,然后采用补加L-谷氨酰胺策略提高L-茶氨酸产量,最后利用HZ016阳离子树脂纯化L-茶氨酸。结果表明:以300 mmol/L L-谷氨酰胺和3 mol/L乙胺盐酸盐为底物,加入30 mg/m L湿菌体,在p H10.5、30℃下连续反应6 h时L-茶氨酸产量最高达34.65 g/L,摩尔转化率为64.88%。通过分批添加L-谷氨酰胺,L-茶氨酸产量最高可达60.20 g/L。经过分离纯化L-茶氨酸的质量分数达到94.60%。

The recombinant Escherichia coli（ Rosetta （DE3）/pET28a-GGT） was used to catalyze L-glutamine and ethylamine · HC1 to produce L-theanine. The optimal conditions for the enzymatic synthesis of L-theanine were investigated. The L-glutamine feeding strategy was applied to increase L-theanine production. Finally L-theanine was purified by using the HZ016 cation-exchange resin. The results show that, 34.65 g/L L-theanine is produced with molar conversion rate of 64.88% when 300 mmol/L L-glutamine, 3 mol/L ethylamine and 30 mg/mL recombinant cellsare added in the solution of pH 10.5 at 30 ℃. With the feeding strategy, 60.20 g/L L-glutamine is produced. The purity of L-theanine reaches 94.60% after purification.