Methods and compositions for the oxidation of short alkanes by engineered microorganisms expressing recombinant enzymes is described, along with methods of use.

The present invention relates to a yeast cell, in particular a recombinant yeast cell, the cell lacking enzymatic activity needed for the NADH-dependent glycerol synthesis or the cell having a reduced enzymatic activity with respect to the NADH-dependent glycerol synthesis compared to its corresponding wild-type yeast cell, the cell comprising one or more heterologous nucleic acid sequences encoding an NAD.sup.+-dependent acetylating acetaldehyde dehydrogenase (EC 1.2.1.10) activity. The invention further relates to the use of a cell according to the invention in the preparation of ethanol.

Multi-carbon compounds such as ethanol, n-butanol, sec-butanol, isobutanol, tert-butanol, fatty (or aliphatic long chain) alcohols, fatty acid methyl esters, 2,3-butanediol and the like, are important industrial commodity chemicals with a variety of applications. The present invention provides metabolically engineered host microorganisms which metabolize methane (CH.sub.4) as their sole carbon source to produce multi-carbon compounds for use in fuels (e.g., bio-fuel, bio-diesel) and bio-based chemicals. Furthermore, use of the metabolically engineered host microorganisms of the invention (which utilize methane as the sole carbon source) mitigate current industry practices and methods of producing multi-carbon compounds from petroleum or petroleum-derived feedstocks, and ameliorate much of the ongoing depletion of arable food source farmland currently being diverted to grow bio-fuel feedstocks, and as such, improve the environmental footprint of future bio-fuel, bio-diesel and bio-based chemical compositions.

A method for producing an objective substance such as vanillin and vanillic acid is provided. An objective substance is produced from a carbon source or a precursor of the objective substance by using a microorganism having an objective substance-producing ability, which microorganism has been modified so that the activity of enolase is reduced.

The present disclosure discloses an alcohol dehydrogenase mutant and application thereof in synthesis of diaryl chiral alcohols, and belongs to the technical field of bioengineering. The alcohol dehydrogenase mutant of the present disclosure has excellent catalytic activity and stereoselectivity, and may efficiently catalyze the preparation of a series of chiral diaryl alcohols in R- and S-configurations. By coupling alcohol dehydrogenase of the present disclosure to glucose dehydrogenase or formate dehydrogenase, the synthesis of chiral diaryl alcohol intermediates of various antihistamines may be achieved. Compared with the prior art, a method for preparing diaryl chiral alcohols through asymmetric catalytic reduction using the alcohol dehydrogenase of the present disclosure has the advantages of simple and convenient operation, high substrate concentration, complete reaction and high product purity, and has great industrial application prospects.

The present invention relates to methods of upgrading biomass to provide useful chemical intermediates, fuels, amino acids, nutrients, etc. In particular examples, the biomass is a by-product of ethanol production and is mainly used as high-protein feed. Described herein are methods for upgrading such biomass, such as by implementing pre-treatment conditions and by employing fermentation conditions including modified organisms.

Disclosed is an alcohol dehydrogenase mutant and application thereof in cofactor regeneration, and belongs to the technical fields of enzyme engineering and bioengineering. The alcohol dehydrogenase mutant is obtained by mutating valine at position 84 and/or tyrosine at position 127 in alcohol dehydrogenase having an original amino acid sequence as set forth in SEQ ID No. 1. The alcohol dehydrogenase mutant has high activity for a variety of alcohol co-substrates, and can catalyze these enzyme co-substrates for the regeneration of cofactor NADPH. Compared with the wild-type alcohol dehydrogenase KpADH, the alcohol dehydrogenase mutant has higher activity and catalytic efficiency, and for co-substrate 1,4-butanediol, its k.sub.cat value can be up to 75.9 min.sup.1, its k.sub.cat/K.sub.m value can be up to 2009 min.sup.1.Math.M.sup.1, and its K.sub.m value can be as low as 11.3 mM. Therefore, the alcohol dehydrogenase mutant has a higher value in industrial application.

Described herein are non-natural NAD.sup.+-dependent alcohol dehydrogenases (ADHs) capable of at least two fold greater conversion of methanol or ethanol to formaldehyde or acetaldehyde, respectively, as compared to its unmodified counterpart. Nucleic acids encoding the non-natural alcohol dehydrogenases, as well as expression constructs including the nucleic acids, and engineered cells comprising the nucleic acids or expression constructs are described. Also described are engineered cells expressing a non-natural NAD.sup.+-dependent alcohol dehydrogenase, optionally include one or more additional metabolic pathway transgene(s), methanol metabolic pathway genes, target product pathway genes, cell culture compositions including the cells, methods for promoting production of the target product or intermediate thereof from the cells, compositions including the target product or intermediate, and products made from the target product or intermediate.

The present application relates to a technical field of Lactobacillus strains, specifically, to a method of producing calcium propionate by using Lactobacillus reuteri. The method is that: the Lactobacillus reuteri with inactivated alcohol dehydrogenase and 1,2-propanediol are mixed, then grown and reproduced, and then an enrichment culture is conducted; and, after enrichment culture, a strain is placed into a culture medium containing calcium ion for a fermentation culture, then calcium propionate is obtained.

Provided are genetically engineered microorganism that catalyze the synthesis of propane and/or butanol from a suitable substrate such as glucose. Also provided are methods of engineering said genetically engineered microorganism and methods of producing propane and/or butanol using the genetically engineered microorganism.