Recombinant Escherichia coli capable of increasing yield of L-threonine, and construction method and application thereof

• Main Authors: ZHAI XIUCHAO, CHEN TAICHI, LI JIANGHUA, LIU LONG, DU GUOCHENG, ZHOU RENKAI, LYU XUEQIN
• Format: Patent
• Language: Chinese; English
• Published: 17.04.2020
• Subjects: BEER; BIOCHEMISTRY; CHEMISTRY; COMPOSITIONS THEREOF; CULTURE MEDIA; ENZYMOLOGY; FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIREDCHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERSFROM A RACEMIC MIXTURE; METALLURGY; MICROBIOLOGY; MICROORGANISMS OR ENZYMES; MUTATION OR GENETIC ENGINEERING; PROCESSES USING MICROORGANISMS; PROPAGATING, PRESERVING OR MAINTAINING MICROORGANISMS; SPIRITS; VINEGAR; WINE

The invention discloses a recombinant Escherichia coli capable of increasing the yield of L-threonine, and a construction method and an application thereof. Escherichia coli CICC20905 is used as an original strain, error-prone PCR and CRISPR-Cas9 gene editing technologies are adopted, a key gene dapA of an L-threonine synthesis competitive pathway and a threonine dehydrogenase encoding gene tdh are knocked out, then L-threonine is randomly mutated by using a gene random mutation kit to synthesize a promoter sequence PthrA of a related gene thrA, and 5 recombinant bacteria ECT1, ECR2 and ECT3-1-ECT3-3 are constructed. The yield of a fermentation tank of L-threonine is remarkably increased through ECT3-2 and reaches 120 g/l, and a foundation is laid for further metabolic engineering transformation of Escherichia coli to produce L-threonine. 本发明公开了一种L-苏氨酸产量提高的重组大肠杆菌及其构建方法与应用。本发明是以大肠杆菌CICC20905作为出发菌株，采用易错PCR和CRISPR-Cas9基因编辑技术，敲除L-苏氨酸合成竞争途径关键基因dapA和敲除苏氨酸脱氢酶编码基因tdh后，利用基因随机突变试剂盒随机突变L-苏氨酸合成相关基因thrA的启动子序列P，构建得到5株重组菌EC