摘要
L-茶氨酸是茶叶中一种独特的非蛋白质氨基酸。γ-谷氨基甲酰胺合成酶可以催化L-谷氨酸、乙胺和ATP合成L-茶氨酸,但反应成本较高。为了提高L-茶氨酸的生产效率,该研究开发了直接发酵生产L-茶氨酸的新方法。首先,在大肠杆菌基因组上双拷贝Methylovorus mays来源的γ-谷氨酰甲胺合成酶基因gmas,获得了一株遗传稳定的用于L-茶氨酸生产的重组菌株。其次,在5 L罐中采用流加乙胺的方式发酵20 h,L-茶氨酸产量达到30.45 g/L,糖酸转化率达到20.17%。最后,根据L-茶氨酸的物化性质拟定出合适的分离提取路线,从发酵液中获得了98.51%纯度的L-茶氨酸成品,总提取收率可达到70.34%。该方法操作简单,原料成本较低,具有较好的工业应用前景。
L-theaine is a unique non-protein amino acid in tea.The L-theaine can be synthesized from L-glutamate and ethylamine byγ-glutamylmethylamide synthetase with assistance of ATP,but the cost of process is high.In order to improve the production efficiency of L-theanine,a new direct fermentation method was developed.Firstly,a genetically stable recombinant Escherichia coli strain was constructed by integrating double copy of theγ-glutamylmethylamine synthase gene(gmas),which derived from Methylovorus mays,into the genome.Subsequently,fed-batch fermentation was carried out in a 5 L fermenter with ethylamine supplement.The yield of L-theanine reached 30.45 g/L,and the conversion rate of glucose to L-theanine reached 20.17%after 20 h fermentation.Additionally,a suitable separation and extraction route was established according to the knowledge about the physicochemical properties of L-theanine.The whole extraction yield of L-theanine from the fermentation broth was 70.34%with a purity of 98.51%.The method has the advantages of simple operation and cheap raw materials,and has broad prospects for industrial application.
作者
张通
龙科艺
曹华杰
吴思佳
元跃
陈宁
范晓光
ZHANG Tong;LONG Keyi;CAO Huajie;WU Sijia;YUAN Yue;CHEN Ning;FANXiaoguang(College of Biotechnology,Tianjin University of Science&Technology,Tianjin 300457,China;Henan Julong Biological Engineering Co.,Ltd,Ruzhou 467500,China;Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control,Tianjin 300457,China)
出处
《食品与发酵工业》
CAS
CSCD
北大核心
2019年第22期6-11,共6页
Food and Fermentation Industries
基金
国家自然科学基金(31700037)
天津市自然科学基金(18JCQNJC79200)
大学生创新创业训练计划项目(201910057089)
工业微生物优良菌种选育与发酵技术公共服务平台项目(17PTGCCX00190)
关键词
L-茶氨酸
γ-谷氨酰甲胺合成酶
发酵
分离提取
L-theanine
γ-glutamylmethylamine synthase
fermentation
separation and extraction
作者简介
第一作者:张通,硕士;通讯作者:范晓光,硕士,讲师,E-mail:xiaoguangfan@tust.edu.cn。
