Genetically modified microorganisms that have the ability to convert carbon substrates into chemical products such as 2,3-BDO are disclosed. For example, genetically modified methanotrophs that are capable of generating 2,3-BDO at high titers from a methane source are disclosed. Methods of making these genetically modified microorganisms and methods of using them are also disclosed.

The present invention provides a genetically modified lactic acid bacterium capable of producing diacetyl under aerobic conditions. Additionally the invention provides a method for producing diacetyl using the genetically modified lactic acid bacterium under aerobic conditions in the presence of a source of iron-containing porphyrin and a metal ion selected from Fe.sup.3+, Fe.sup.2+ and Cu.sup.2+. The lactic acid bacterium is genetically modified by deletion of those genes in its genome that encode polypeptides having lactate dehydrogenase (E.C 1.1.1.27/E.C.1.1.1.28); -acetolactate decarboxylase (E.C 4.1.1.5); water-forming NADH oxidase (E.C. 1.6.3.4); phosphotransacetylase (E.C.2.3.1.8) activity; and optionally devoid of or deleted for genes encoding polypeptides having diacetyl reductase ((R)-acetoin forming; EC:1.1.1.303); D-acetoin reductase; butanediol dehydrogenase ((R,R)-butane-2,3-diol forming; E.C. 1.1.1.4/1.1.1.-) and alcohol dehydrogenase (E.C. 1.2.1.10) activity. The invention provides for use of the genetically modified lactic acid bacterium for the production of diacetyl and a food product.

Genetically modified microorganisms that have the ability to convert carbon substrates into chemical products such as 2,3-BDO; 1,4-BDO; isobutyraldehyde; isobutanol; 1-butanol; n-butanol; ethanol; fatty alcohols; and fatty acid methyl ester are disclosed. For example, genetically modified methanotrophs that are capable of generating 2,3-BDO; 1,4-BDO; isobutyraldehyde; isobutanol; 1-butanol; n-butanol; ethanol; fatty alcohols; and fatty acid methyl ester at high titers from a methane source are disclosed. Methods of making these genetically modified microorganisms and methods of using them are also disclosed. These microorganisms and methods make use of molecular switches to regulate gene expression.

Genetically modified microorganisms that have the ability to convert carbon substrates into chemical products such as 2,3-BDO are disclosed. For example, genetically modified methanotrophs that are capable of generating 2,3-BDO at high titers from a methane source are disclosed. Methods of making these genetically modified microorganisms and methods of using them are also disclosed.

The present invention discloses a bacterium and an obtaining method and application thereof. The bacterium has a property of coproducing 1,3-propanediol and D-lactic acid. Further, the bacterium is Klebsiella oxytoca, including Klebsiella oxytoca PDL-5 CCTCC M 2016185. The obtaining method of the bacterium may be to obtain the bacterium by directly screening wild bacteria that satisfy conditions from the environment or performing gene engineering modification to wild bacteria. The present invention has the advantages that the bacteria can coproduce 1,3-propanediol and D-lactic acid through fermentation, the molar conversion rate and the concentration of the two products are very high, the types of byproducts are few, the concentration is low, the product extraction process is simplified, the high-efficiency biological production of 1,3-propanediol and D-lactic acid can be realized, and the industrial application prospect is very great.

A method for producing an L-amino acid such as L-glutamic acid is provided. An L-amino acid is produced by culturing in a culture medium a bacterium belonging to the family Enterobacteriaceae and having an L-amino acid-producing ability, and collecting the L-amino acid from the culture medium and/or cells of the bacterium, wherein the bacterium has been modified to have one or more of the following modifications: (A) modification of reducing the activity of a BudA protein; (B) modification of reducing the activity of a BudB protein; (C) modification of reducing the activity of a BudC protein; (D) modification of reducing the activity of a PAJ_3461 protein; (E) modification of reducing the activity of a PAJ_3462 protein; and (F) modification of reducing the activity of a PAJ_3463 protein.

The invention relates to an in vitro cell-free expression system incorporating a novel inorganic polyphosphate-based energy regeneration system. In certain embodiments, the invention includes a cell-free expression system where the cellular energy source, ATP, is regenerated from inorganic polyphosphate using a dual enzyme system. In this embodiment, this dual enzyme system may include thermostable Adenosyl Kinase, and/or Polyphosphate Kinase enzymes.

The present invention relates to a recombinant microorganism for producing D() 2,3-butanediol, wherein a gene encoding an enzyme for converting acetoin into D() 2,3-butanediol is introduced into a microorganism having a pathway for converting acetoin into 2,3-butanediol. In addition, the present invention relates to a method for producing D() 2,3-butanediol by using the recombinant microorganism.

Disclosed are a recombinant yeast for producing 2,3-butanediol and a method for producing 2,3-butanediol using the same. By introducing Candida tropicalis-derived Pdc, which is less active than its own pyruvate decarboxylase (Pdc), into the cells of the strain, the recombinant yeast can synthesize acetyl-CoA, while avoiding production of ethanol, thereby increasing the strain growth rate and the substrate consumption rate and ultimately greatly improving productivity of 2,3-butanediol.

Disclosed is a method for producing 2,3-butanediol. Conventional methods for producing 2,3-butanediol using Saccharomyces cerevisiae (yeast) inevitably cause production of a great amount of glycerol as a by-product, in addition to production of 2,3-butanediol. However, the yeast strain according to the present invention can produce 2,3-butanediol with high purity, high yield and high productivity, while inhibiting production of glycerol.

The present invention discloses a bacterium and an obtaining method and application thereof. The bacterium has a property of coproducing 1,3-propanediol and D-lactic acid. Further, the bacterium is Klebsiella oxytoca, including Klebsiella oxytoca PDL-5 CCTCC M 2016185. The obtaining method of the bacterium may be to obtain the bacterium by directly screening wild bacteria that satisfy conditions from the environment or performing gene engineering modification to wild bacteria. The present invention has the advantages that the bacteria can coproduce 1,3-propanediol and D-lactic acid through fermentation, the molar conversion rate and the concentration of the two products are very high, the types of byproducts are few, the concentration is low, the product extraction process is simplified, the high-efficiency biological production of 1,3-propanediol and D-lactic acid can be realized, and the industrial application prospect is very great.