为了高效合成茶氨酸,本研究通过将荧光假单胞菌GS基因转接入pET32a质粒中,再将重组质粒转化到E. coli BL21中,构建了一种生物合成茶氨酸的基因工程菌。工程菌株经0.1βmmol/L IPTG,28℃诱导表达,湿菌体的酶活达到41.79 U/mg prot,大约是出发菌株E. coli BL21的126.64倍。工程菌催化L-谷氨酸钠和盐酸乙胺反应生成茶氨酸的产量达到6.2 g/L,其催化L-谷氨酰胺和盐酸乙胺反应生成茶氨酸的能力较出发菌株E. coli BL21有显著提高。
An experiment on the construction of E. coli recombinant strain for theanine biosynthesis with GS gene embedded was reported. In this experiment, Glutamine Synthetase gene in E. coli BL21 was ligated with the pET32a vector in order to produce theanine. The ligation product was transformed to E. coli BL21 and the engineered E. coli strain was constructed successfully. The glutamine Synthetase was expressed with induction of 0.1 mmol/L IPTG in 28℃. The activity of γ-glutamyl transpeptidase of the engineered strain of fresh E. coil engineered strain reached 41.79 U /mg prot, and was 126.64 times higher than that of the original strain one and the yield of theanine from L-Gln and ethylamine was 6.3 mg/ml. The ability of theanine biosynthesis of recombinant was enhanced obviously compared with that of original E. coli BL21.
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