A Saccharomyces cerevisiae strain with high yield of ethyl butyrate and a construction method and an application thereof are provided. The strain is obtained by over-expressing in the starting strain acetyl coenzyme A acyl transferase gene Erg10, 3-hydroxybutyryl coenzyme A dehydrogenase gene Hbd, 3-hydroxybutyryl coenzyme A dehydratase gene Crt, trans-2-enoyl coenzyme A reductase gene Ter, and alcohol acyl transferase gene AAT. Compared to the starting bacteria not producing ethyl butyrate, the yield of ethyl butyrate of the constructed strain reaches 77.33±3.79 mg/L, the yield of the ethyl butyrate of the strain with double copy expression of gene Ter and gene AAT reaches 99.65±7.32 mg/L, increased by 28.9% compared with the EST strain, and 40.93±3.18 mg/L of ethyl crotonate is unexpectedly produced.

A process of producing methacrylic acid and/or derivatives thereof including the following steps: (a) biologically converting isobutyryl-CoA into methacrylyl-CoA by the action of an oxidase; and (b) converting methacrylyl-CoA into methacrylic acid and/or derivatives thereof. The invention also extends to microorganisms adapted to conduct the steps of the process.

The disclosure discloses an Aspergillus niger engineered strain for reducing byproduct succinic acid in a fermentation process of L-malic acid. The Aspergillus niger engineered strain is an Aspergillus niger engineered strain in which fumaric acid reductase frdA and fumaric acid reductase flavoprotein subunit frdB are simultaneously knocked out. The disclosure provides an frdA and frdB gene double-knockout Aspergillus niger strain, and a method for greatly reducing byproduct succinic acid in a fermentation process of L-malic acid. By the disclosure, the byproduct succinic acid accumulated in a production process of malic acid through fermentation of Aspergillus niger is significantly reduced, a cost in a downstream separation and purification process of malic acid is decreased, and good strains are provided for producing malic acid via industrial fermentation.

The present invention is within the field of industrial protein production. The invention provides a novel expression system using dehydroorotate dehydrogenase (DHODH) as a selection marker in combination with leflunomide or a metabolite thereof, notably for use in mammalian cell lines. Expression vectors encoding DHODH, cell lines comprising said vectors and methods of producing recombinant proteins are also provided.

The present invention provides engineered galactose oxidase (GOase) enzymes, polypeptides having GOase activity, and polynucleotides encoding these enzymes, as well as vectors and host cells comprising these polynucleotides and polypeptides. Methods for producing GOase enzymes are also provided. The present invention further provides compositions comprising the GOase enzymes and methods of using the engineered GOase enzymes. The present invention finds particular use in the production of pharmaceutical and other compounds.

Provided herein are genetically modified Issatchenkia yeast and fermentation methods for producing succinic acid.

Described herein is a PAH-degrading enzyme mixture obtained from a culture of PAH-utilizing microorganisms having been grown in presence of one or more enzyme inducers. Related methods and devices are also described.

The invention provides recombinant DNA molecules useful for providing efficient expression of proteins in transgenic plants, as well as compositions and methods for using the recombinant DNA molecules. In particular embodiments, the invention provides recombinant DNA molecules and constructs comprising sequences encoding transit peptides and operably linked sequences conferring herbicide tolerance.

Yeast cells having a reductive TCA pathway from pyruvate or phosphoenolpyruvate to succinate, and which include at least one exogenous gene overexpressing an enzyme in that pathway, further contain an exogenous transhydrogenase gene.

A process of producing methacrylic acid and/or derivatives thereof including the following steps: (a) biologically converting isobutyryl-CoA into methacrylyl-CoA by the action of an oxidase; and (b) converting methacrylyl-CoA into methacrylic acid and/or derivatives thereof. The invention also extends to microorganisms adapted to conduct the steps of the process.