Tianjin University of Science and Technology

Qian Ma

Ning Chen

Xixian Xie

Yanjun Li

Qingyang Xu

Xiaoguang Fan

Heyun Wu

Chenglin Zhang

Jie Ma

Qiang Li

Guoliang Li

Xuejiao Wu

Fangqing Yan

Hongchao Zhang

The present disclosure relates to the field of genetic engineering, especially relates to a xylose-induced genetically engineered bacteria used for producing ectoine as well as a construction method and use thereof. The genetically engineered bacteria is constructed by heterologously expressing the ectABC gene cluster fromon thechromosome, using the promoter of xylose transporter coding gene xylF to control the RNA polymerase from T7 bacteriophage, reconstructing a synthesis pathway of ectoine and constructing a plasmid-free system, and enhancing the expression of target genes by a strong promoter T7; the yield of ectoine reached 12-16 g/L after 20-28 h fermentation in shake flask, and reached 35-50 g/L after 24-40 h fermentation in a 5 L fermentor.

Xylose-induced genetically engineered bacteria used for producing ectoine and use 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

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Tianjin, China

Qian Ma