Related are a recombinant microorganism for producing L-valine, a construction method and an application thereof. Through transferring an amino acid dehydrogenase gene and/or activating activity of a transhydrogenase and/or a NAD kinase, reducing power of NADPH in cell is increased, the titer and yield of L-valine generated by Escherichia coli are improved, and the production of L-valine by one-step anaerobic fermentation is achieved.

Related are a recombinant microorganism for producing L-valine, a construction method and an application thereof. Through enhancing amino acid dehydrogenase activity of L-valine fermentation strain, and/or activating an Entner-Doudoroff (ED) metabolic pathway, a problem in L-valine fermentation process that reducing power is unbalanced is solved, thereby the titer and yield of L-valine produced by Escherichia coli are improved, and L-valine was produced by one-step anaerobic fermentation.

The present invention discloses a single-cell factory for efficiently synthesizing -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 -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.Math.L.sup.1, the space-time yield is 10.2 g.Math.L.sup.1.Math.h.sup.1, and a practical effective strategy is provided for industrialized production.

Embodiments of the present disclosure relate to a D-amino acid oxidase mutant and application in preparing L-glufosinate thereof. The D-amino acid oxidase mutant has an amino acid substitution at at least one of position 62 and position 226 of an amino acid sequence of the D-amino acid oxidase mutant when compared to an amino acid sequence of a D-amino acid oxidase as set forth in SEQ ID NO. 1, the position 62 and position 226 being defined with reference to SEQ ID NO. 1, and the amino acid sequence of the D-amino acid oxidase mutant having at least 90% identity to SEQ ID NO. 1.

The present disclosure provides recombinant bacterial cells that have been engineered with genetic circuitry which allow the recombinant bacterial cells to sense a patient's internal environment and respond by turning an engineered metabolic pathway on or off. When turned on, the recombinant bacterial cells complete all of the steps in a metabolic pathway to achieve a therapeutic effect in a host subject. These recombinant bacterial cells are designed to drive therapeutic effects throughout the body of a host from a point of origin of the microbiome. Specifically, the present disclosure provides recombinant bacterial cells that comprise an amino acid catabolism enzyme for the treatment of diseases and disorders associated with amino acid metabolism, including cancer, in a subject. The disclosure further provides pharmaceutical compositions and methods of treating disorders associated with amino acid metabolism, such as cancer.

The present invention discloses a single-cell factory for efficiently synthesizing -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 -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.Math.L.sup.1, the space-time yield is 10.2 g.Math.L.sup.1.Math.h.sup.1, and a practical effective strategy is provided for industrialized production

Embodiments of the present disclosure relate to a D-amino acid oxidase mutant and application in preparing L-glufosinate thereof. The D-amino acid oxidase mutant has an amino acid substitution at at least one of position 62 and position 226 of an amino acid sequence of the D-amino acid oxidase mutant when compared to an amino acid sequence of a D-amino acid oxidase as set forth in SEQ ID NO. 1, the position 62 and position 226 being defined with reference to SEQ ID NO. 1, and the amino acid sequence of the D-amino acid oxidase mutant having at least 90% identity to SEQ ID NO. 1.

The present disclosure relates to a recombinant microorganism capable of efficiently producing L-leucine and an L-leucine production method using the same. The production method includes: (p) incubating a recombinant microorganism having an L-leucine biosynthesis pathway or a processed product of microbial cells thereof in a predetermined culture medium (X) to thereby produce L-leucine; and (q) recovering a fraction including the L-leucine from the predetermined culture medium (X). The recombinant microorganism includes, in an expressible form, a gene encoding an amino acid dehydrogenase. The amino acid dehydrogenase at least has a catalytic effect on an L-leucine production reaction in the L-leucine biosynthesis pathway.