A recombinant yeast having a reduced pyruvate decarboxylase activity, in the gnome of which has been inserted: one or more nucleic acids encoding an acetolactate synthase or ALS, one or more nucleic acids encoding an acetolactate decarboxylase or ALD, one or more nucleic acids encoding a butancdiol dehydrogenase or BDH, and one or more copies of a nucleic acids encoding a NADH oxidase or NOXE.

The present invention relates to a recombinant yeast having a reduced pyruvate decarboxylase activity, in the genome of which has been inserted:one or more nucleic acids encoding an acetolactate synthase or ALS,one or more nucleic acids en coding an acetolactate decarboxylase or ALD, andone or more copies of a nucleic acids encoding a NADH oxidase or NOXE.

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.

Genetically modified microorganisms that have the ability to convert carbon substrates into chemical products such as isobutanol are disclosed. For example, genetically modified methanotrophs that are capable of generating isobutanol 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 for compositions and methods for producing sorghum crop plants that are resistant to herbicides. In particular, the present invention provides for sorghum plants, plant tissues and plant seeds that contain altered acetolactate synthase (ALS) genes and proteins that are resistant to inhibition by herbicides that normally inhibit the activity of the ALS protein.

The present invention provides for compositions and methods for producing sorghum crop plants that are resistant to herbicides. In particular, the present invention provides for sorghum plants, plant tissues and plant seeds that contain altered acetolactate synthase (ALS) genes and proteins that are resistant to inhibition by herbicides that normally inhibit the activity of the ALS protein.

A transformant obtained by introducing (a) a lactate dehydrogenase gene and/or (b) a malate/lactate dehydrogenase gene into a Hydrogenophilus bacterium efficiently produces lactic acid through use of carbon dioxide as a sole carbon source. Parageobacillus thermoglucosidasius ldh gene, Geobacillus kaustophilus ldh gene and Thermus thermophilus ldh gene of lactate dehydrogenases, and Thermus thermophilus mldh gene and Meiothermus ruber mldh-1 and mldh-2 genes of malate/lactate dehydrogenases are preferable in that they have good lactic acid production efficiency.

Methods of screening for dihydroxy-acid dehydratase (DHAD) variants that display increased DHAD activity are disclosed, along with DHAD variants identified by these methods. Such enzymes can result in increased production of compounds from DHAD requiring biosynthetic pathways. Also disclosed are isolated nucleic acids encoding the DHAD variants, recombinant host cells comprising the isolated nucleic acid molecules, and methods of producing butanol.

Methods for the fermentative production of four carbon alcohols is provided. Specifically, butanol, preferably isobutanol is produced by the fermentative growth of a recombinant bacterium expressing an isobutanol biosynthetic pathway.

The present invention relates to a method for producing 1,3-propanediol using a mutant microorganism lacking a 2,3-butanediol synthetic gene, and more particularly to a mutant microorganism wherein a gene encoding lactate dehydrogenase and a gene encoding an enzyme which is involved in 2,3-butanediol synthesis are deleted in a microorganism having the ability to produce 1,3-propanediol from glycerol and wherein a gene encoding pyruvate decarboxylase and a gene encoding aldehyde dehydrogenase are introduced or amplified, and to a method of promoting the production of 1,3-propanediol while inhibiting the production of 2,3-butanediol by using the mutant microorganism. The use of the glycerol-fermenting mutant microorganism according to the present invention can significantly increase the production of 1,3-propanediol while minimizing the production of 2,3-butanediol.