Single-Cell Factory for Efficiently Synthesizing alpha-aminobutyric Acid and Construction and Application thereof

    公开(公告)号:US20190161779A1

    公开(公告)日:2019-05-30

    申请号:US16063651

    申请日:2016-11-17

    Abstract: The present invention discloses a single-cell factory for efficiently synthesizing α-aminobutyric acid and construction and application thereof, which belong to the technical field of microorganisms. The present invention expresses an L-threonine deaminase gene, an L-amino acid dehydrogenase gene and a dehydrogenase gene for providing cofactor NADH cycle in tandem to construct a recombinant Escherichia coli single-cell factory which is used for efficiently synthesizing α-aminobutyric acid. The expression level of the L-threonine deaminase is optimized and controlled by an RBS sequence, so that the problem of transformation inhibition caused by the rapid accumulation of an intermediate product ketobutyric acid is solved, moreover, the expression level of the dehydrogenase for providing cofactor NADH cycle is optimized and controlled by a promoter and an RBS sequence, consequently, the NADH regeneration rate is increased, and ultimately, yield is increased. Utilizing the single-cell factory to carry out whole-cell transformation can reduce obstacles to substances getting in and out, increase the transformation rate and promote the intracellular cycle of cofactors without requiring exogenous addition, and the cost is low. Within 20 h, the yield of the recombinant Escherichia coli single-cell factory in a 5 L fermentation tank is 204 g·L−1, the space-time yield is 10.2 g·L−1·h−1, and a practical effective strategy is provided for industrialized production

    L-ARGININE-GLYCINE AMIDINOTRANSFERASE AND USE THEREOF IN THE PRODUCTION OF GUANIDINOACETIC ACID

    公开(公告)号:US20240344038A1

    公开(公告)日:2024-10-17

    申请号:US18415827

    申请日:2024-01-18

    CPC classification number: C12N9/1003 C12N15/70 C12P13/04 C12Y201/04001

    Abstract: The present invention discloses an L-arginine-glycine amidinotransferase and use thereof in the production of guanidinoacetic acid. In the present invention, through combined multi-site amino acid mutation, a technical effect of significantly improved enzyme activity of the mutant AkAGATT225Q/A258P/L278K than that of the wild-type strain is achieved, providing an application value for large-scale production of guanidinoacetic acid in industry. When the L-arginine-glycine amidinotransferase mutant constructed in the present invention is used in the production of guanidinoacetic acid, by optimizing the conversion conditions, the yield of guanidinoacetic acid is up to 21.4 g/L and the conversion rate is 90.4%, after 24 hrs of reaction in a 1 L reaction system. Compared with the production of guanidinoacetic acid with the raw enzyme, the yield is increased by 49.6%.

    METHOD FOR PRODUCING 1,2-AMINO ALCOHOL COMPOUND BY WHOLE CELL TRANSFORMATION

    公开(公告)号:US20200149077A1

    公开(公告)日:2020-05-14

    申请号:US16682486

    申请日:2019-11-13

    Abstract: The present invention discloses a method for producing a 1,2-amino alcohol compound by utilizing whole-cell transformation, and belongs to the technical field of gene engineering and microorganism engineering. According to the present invention, engineered Escherichia coli co-expresses epoxide hydrolase, alcohol dehydrogenase, ω-transaminase and glutamate dehydrogenase, is capable of realizing whole-cell catalysis of an epoxide in one step to synthesize a 1,2-amino alcohol compound, and meanwhile, can realize regeneration of coenzyme NADP+ and an amino doner L-Glu; alcohol dehydrogenase expressed by the engineered Escherichia coli is RBS optimized alcohol dehydrogenase, and such RBS optimization can control the expression quantity of alcohol dehydrogenase, so that the catalysis rate of alcohol dehydrogenase and transaminase can achieve an optimum ratio, to eliminate influence caused by a rate-limiting step in a catalyzing course.

    Method for Increasing Yield of L-Arginine by Knocking Out Flavin Reductases

    公开(公告)号:US20190153489A1

    公开(公告)日:2019-05-23

    申请号:US16063639

    申请日:2016-07-29

    CPC classification number: C12P13/10 C12N9/0028 C12Y105/01038

    Abstract: The invention discloses a method for increasing the yield of L-arginine by knocking out flavin reductases, and belongs to the technical field of amino acid production by microbial fermentation. Genes frd1 and frd2 for encoding hypothetic NADPH-dependent FMN reductase in Corynebacterium crenatum SDNN403 are over-expressed in E. coli BL21 and are purified to form target proteins Frd181 and Frd188, and functions of the target proteins are identified to obtain a result showing that the proteins Frd181 and Frd188 both are NAD(P)H-dependent flavin reductases producing H2O2. By taking a genome of the Corynebacterium crenatum SDNN403 as a template, frd1 and frd2 gene deletion fragments are obtained by overlap extension PCR; connecting pK18mobsacB to obtain knockout plasmids pK18mobsacB-Δfrd1 and pK18mobsacB-Δfrd2; carrying out electric shock to transform the Corynebacterium crenatum SDNN403; and carrying out secondary screening to obtain recombinant strains 403Δfrd1 and 403Δfrd2. Found by flask shaking fermentation, the yield of L-arginine is obviously increased by knocking out the genes frd1 and frd2.

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