The present disclosure relates to genetically engineered methanotrophic bacteria with the capability of growing on a multi-carbon substrate (e.g., glucose) as a primary or sole carbon source and methods for growing methanotrophic bacteria on the multi-carbon substrate.

The present disclosure provides for production of lactic acid from organic waste or biogas or methane using recombinant methanotrophic bacteria. In one embodiment, the recombinant methanotrophic bacterium includes a heterologous nucleic acid encoding for lactate dehydrogenase (ldh) enzyme. In a further embodiment, the capacity of the recombinant methanotrophic bacterium for producing lactic acid over basal level is increased by overexpression or/and down-regulation or deletion of specified genes. In another embodiment, a process for producing lactic acid from organic waste using the recombinant methanotrophic bacterium is disclosed. The present disclosure provides a cradle to cradle environment-friendly and commercially viable solution for managing organic waste.

Tools and methods for producing organic acids using strains of Monascus which are tolerant to high organic acid concentrations at low pH.

The present disclosure discloses a method for improving production of L-lactic acid (L-LA) by Saccharomyces cerevisiae based on regulation and control of ethanol metabolic flux, and belongs to the technical field of microorganisms. According to the present disclosure, acid-resistant Saccharomyces cerevisiae TJG16 is used as a production strain, an ethanol dehydrogenase gene adhA derived from Bacillus subtilis is introduced to promote conversion of ethanol into acetaldehyde, and a lactate aldolase gene BAL derived from Brucella sp. is introduced to promote synthesis of lactic acid from the acetaldehyde. Moreover, an acetaldehyde dehydrogenase gene ALD6 is knocked out to prevent synthesis of acetic acid from the acetaldehyde, a transcriptional regulatory factor encoding gene GAL80 for regulating and controlling galactose is knocked out, and lactate dehydrogenase LDH is integrated, so that the L-LA is finally increased.

The present invention relates to a method for preparing a D-lactic acid-producing strain modified to inhibit L-lactate dehydrogenase (L-LDH) activity and to introduce D-lactate dehydrogenase (D-LDH) activity in an L-lactic acid-producing strain, a mutated D-lactic acid-producing strain prepared by the above method, and a method for producing D-lactic acid including the steps of culturing the strain and recovering D-lactic acid from the culture media.

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 Cu2+. 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.

The present invention relates to: acid-resistant yeast to which lactic acid productivity is imparted, and in which the conversion of pyruvate into acetaldehyde is inhibited and, consequently, the ethanol production pathway is inhibited; and a method for producing lactic acid by using same.

Provided is a genetically engineered yeast cell having increased NADPH production, a method of increasing a NADPH level in a yeast cell, a method of preparing the genetically engineered yeast cell, and a method of producing lactate using the genetically engineered yeast cell.

Provided is a screening method of discovering genes capable of increasing 1,4-BDO production on the basis of proteomics data. Over-expression of proteins screened by the method, NCgl0630 (citrate synthase) and NCgl2145 (hyperthetical protein), increase 1,4-BDO productivity. The method may lead to screening of a protein associated with 1,4-BDO productivity, thereby increasing 1,4-BDO productivity, and thus, the method may be recognized as being industrially applicable.

Provided is an acid-tolerant yeast cell, a method of producing an organic acid by using the yeast cell, and a method of producing the yeast cell resistant to acid.