A cell may include heterologous polynucleotides encoding a multienzyme complex involved in the metabolic pathway of phenylpropanoids and biosynthesis of a vanilloid or a hydroxybenzaldehyde precursor thereof, which multienzyme complex comprises enzymes for the biosynthesis of coumaric acid and a crotonase.

The present invention relates to control of plant pathogens, particularly fungi or oomycetes, by inhibiting one or more biological functions, particularly by inhibiting saccharopine dehydrogenase gene(s) using RNA interference. The invention provides methods and compositions using RNA interference of plant pathogens target genes for such control. The invention is also directed to methods for making transgenic plants tolerant to said plant pathogens, and to transgenic plants and seeds generated thereof.

The present disclosure discloses a recombinant Escherichia coli for producing rosmarinic acid and application thereof, belonging to the technical fields of genetic engineering and bioengineering. In the present disclosure, FjTA derived from Flavobacterium johnsoniae, endogenous hpaBC derived from E. coli, CbRAS derived from Coleus blumei, HPPR derived from Coleus scutellarioides, and Pc4CL1 derived from Petroselinum crispum are heterologously expressed in E. coli, realizing synthesis of rosmarinic acid. TcTAL derived from Trichosporon cutaneum and tyrC for removing feedback inhibition are introduced, further increasing synthesis throughput of caffeic acid, and PmLAAD derived from Proteus myxofaciens is heterologously expressed, realizing redistribution of L-DOPA. An endogenous gene menl is knocked out, improving the content and stability of a rosmarinic acid precursor. The recombinant strain constructed in the present disclosure can produce rosmarinic acid by fermentation at a yield of up to 511.2 mg/L, providing a new method for industrial production of rosmarinic acid.

Disclosed in the present invention is an L-glutamate dehydrogenase mutant, the sequence of the L-glutamate dehydrogenase mutant being a sequence in which amino acid residue A at position 175 in SEQ ID NO: 1 is mutated to be G, and amino acid residue V at position 386 is mutated to be an amino acid residue having less steric hindrance. Further disclosed in the present invention is an application of the described L-amino acid dehydrogenase mutant in the preparation of L-glufosinate-ammonium or a salt thereof. When the L-glutamate dehydrogenase mutant of the present invention is used to prepare L-glufosinate-ammonium or a salt thereof, compared to an L-glutamate dehydrogenase mutant in which only position 175 or 386 is mutated, the specific enzyme activity is higher. Therefore, the action efficiency of the enzyme is improved, reaction costs are reduced, and industrial production is facilitated.

Provided herein is a non-naturally occurring microbial organism having a methanol metabolic pathway (MMP) that can enhance the availability of reducing equivalents in the presence of methanol. Such reducing equivalents can be used to increase the product yield of organic compounds produced by the microbial organism, such as 1,4-butanediol (BDO). Also provided herein are methods for using such an organism to produce BDO.

The present application provides engineered polypeptides having imine reductase activity, polynucleotides encoding the engineered imine reductases, host cells capable of expressing the engineered imine reductases, and methods of using these engineered polypeptides with a range of ketone and amine substrate compounds to prepare secondary and tertiary amine product compounds.

The present application provides engineered polypeptides having imine reductase activity, polynucleotides encoding the engineered imine reductases, host cells capable of expressing the engineered imine reductases, and methods of using these engineered polypeptides with a range of ketone and amine substrate compounds to prepare secondary and tertiary amine product compounds.

A method for preparing (S)-nicotine by reduction includes conducting a reduction process on an alkene compound as shown in Formula I and/or an iminium cation compound as shown in Formula II, thereby producing (S)-nicotine. The method is simple, safe, reliable, and yields both high purity and high quantities of (S)-nicotine production.

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 H.sub.2O.sub.2. 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-frd1 and pK18mobsacB-frd2; carrying out electric shock to transform the Corynebacterium crenatum SDNN403; and carrying out secondary screening to obtain recombinant strains 403frd1 and 403frd2. Found by flask shaking fermentation, the yield of L-arginine is obviously increased by knocking out the genes frd1 and frd2.

The present application provides engineered polypeptides having imine reductase activity, polynucleotides encoding the engineered imine reductases, host cells capable of expressing the engineered imine reductases, and methods of using these engineered polypeptides with a range of ketone and amine substrate compounds to prepare secondary and tertiary amine product compounds.