Tianjin University of Science and Technology

Henan Julong Biological Engineering Co., Ltd

Other

Xiaoguang Fan

Ning Chen

Qingyang Xu

Yuhang Zhou

Jing Li

Jiajia Teng

Mengtao Zhang

Yuanqing Ji

Xiaodong Liu

Yongchao Liu

Bochao Liu

Shuai Liu

Chaochao Sun

Jun Yang

Yanjun Li

Xixian Xie

Heyun Wu

Qian Ma

Chenglin Zhang

Qiang Li

Huajie Cao

Guoliang Li

Pei Xie

Junyu Tian

The present invention belongs to the bioengineering field, and relates to a method for fermentation production of L-theanine by using angenetically engineered bacterium. The engineered bacterium is obtained by serving a strain as an original strain, wherein the strain is obtained after performing a single copy of T7RNAP, a dual copy of gmas, xylR knockout, and sucCD knockout on anW3110 genome, and by integrating genes xfp, pta, acs, gltA, and ppc, and knocking out ackA on the genome. The present invention has a high yield, and stable production performance; after 20-25 h, L-theanine has a titer of 75-80 g/L, and the yield is up to 52-55%. The fermentation broth is purified by membrane separation in combination with a cation-anion resin series technique. Moreover, the one-step crystallization yield is 72.3% and the L-theanine final product has a purity of 99%.

Method for producing L-theanine via fermentation by a genetically engineered bacterium and the application thereof

The disclosure discloses a genetically engineered strain for sarcosine production as well as a construction method and application. The genetically engineered strain is obtained by usingas a host and by integrating a single copy of imine reductase gene dpkA on its genome; singly copying citrate synthase gene gltA; knocking out glyoxylate cycle inhibitor gene iclR; knocking out malate synthase gene aceB; integrating a single copy of isocitrate lyase gene aceA; integrating a single copy of membrane-bound transhydrogenase gene pntAB; knocking out 2-ketate reductase gene ycdW; integrating a single copy of phosphoenolpyruvate carboxylase gene ppc; and knocking out pyruvate kinase gene pykF. After system metabolism transformation, the engineered strain can synthesize sarcosine with glucose and methylamine as main raw materials. The sarcosine titer can reach 10 g/L after fermentation for 30 h in a 5 L fermenter.

Genetically engineered bacterium for sarcosine production as well as construction method and application

Genetically engineered bacterium ofand method for fermentation production of L-theanine thereof

The present disclosure relates to a genetically engineered strain with high production of uridine and its construction method and application. The strain was constructed as follows: heterologously expressing pyrimidine nucleoside operon sequence pyrBCAKDFE (SEQ ID NO:1) on the genome ofprompted by strong promoter Pto reconstruct the pathway of uridine synthesis; overexpressing the autologous prsA gene coding PRPP synthase by integration of another copy of prsA gene promoted by strong promoter Pon the genome; deficiency of uridine kinase, uridine phosphorylase, ribonucleoside hydrolase, homoserine dehydrogenase I and ornithine carbamoyltransferase. When the bacteria was used for producing uridine, 40-67 g/L uridine could be obtained in a 5 L fermentor after fermentation for 40-70 h using the technical scheme provided by the disclosure with the maximum productivity of 0.15-0.25 g uridine/g glucose and 1.5 g/L/h respectively which is the highest level of fermentative producing uridine reported at present.

Genetically engineered bacterium used for producing uridine with high-yield

Growing community of inventors

Tianjin, China

Xiaoguang Fan