Provided herein are methods, compositions, and non-naturally occurring microbial organism for preparing compounds such as1-butanol, butyric acid, succinic acid, 1,4-butanediol, 1-pentanol, pentanoic acid, glutaric acid, 1,5-pentanediol, 1-hexanol, hexanoic acid, adipic acid, 1,6-hexanediol, 6-hydroxy hexanoic acid, ?-Caprolactone, 6-amino-hexanoic acid, ?-Caprolactam, hexamethylenediamine, linear fatty acids and linear fatty alcohols that are between 7-25 carbons long, linear alkanes and linear ?-alkenes that are between 6-24 carbons long, sebacic acid and dodecanedioic acid comprising: a) converting a C.sub.N aldehyde and pyruvate to a C.sub.N+3 ?-hydroxyketone intermediate through an aldol addition; and b) converting the C.sub.N+3 ?-hydroxyketone intermediate to the compounds through enzymatic steps, or a combination of enzymatic and chemical steps.

The invention relates to a recombinant cell, preferably a yeast cell comprising one or more genes coding for an enzyme having glycerol dehydrogenase activity, one or more genes coding dihydroxyacetone kinase (E.C. 2.7.1.28 and/or E.C. 2.7.1.29); one or more genes coding for an enzyme in an acetyl-CoA-production pathway and one or more genes coding for an enzyme having at least NAD.sup.+ dependent acetylating acetaldehyde dehydrogenase activity (EC 1.2.1.10 or EC 1.1.1.2), and optionally one or more genes coding for a glycerol transporter. This cell can be used for the production of ethanol and advantageously produces little or no glycerol.

The invention relates to a genetically engineered bacterium having an enzyme that converts 3-hydroxyisovaleryl-CoA to 3-hydroxyisovalerate and an enzyme that converts 3-hydroxyisovalerate to isobutylene. Typically, the bacterium is capable of producing isobutylene from a gaseous substrate containing CO, CO.sub.2, and/or H.sub.2, such as syngas or an industrial waste gas.

The present invention provides for a mechanism to reduce glycerol production and increase nitrogen utilization and ethanol production of recombinant microorganisms. One aspect of this invention relates to strains of S. cerevisiae with reduced glycerol productivity that get a kinetic benefit from higher nitrogen concentration without sacrificing ethanol yield. A second aspect of the invention relates tometabolic modifications resulting in altered transport and/or intracellular metabolism of nitrogen sources present in corn mash.

The invention relates to a genetically engineered bacterium having an enzyme that converts acetyl-CoA to acetoacetyl-CoA, an enzyme that converts acetoacetyl-CoA to 3-hydroxybutyryl-CoA, and an enzyme that converts 3-hydroxybutyryl-CoA to 3-hydroxybutyrate. The bacterium may also have enzymes to produce other downstream products, such as 3-hydroxybutyryaldehyde, and 1,3-butanediol. Typically, the bacterium is capable of producing these products from a gaseous substrate, such as syngas or an industrial waste gas.

The present invention relates to microorganisms and polypeptides for detoxifying aldehydes associated with industrial fermentations. In particular, a heat-stable, NADPH- and iron-dependent alcohol dehydrogenase was cloned from Thermoanaerobacter pseudethanolicus 39E and displayed activity against a number of aldehydes including inhibitory compounds that are produced during the dilute-acid pretreatment process of lignocellulosic biomass before fermentation to biofuels. Methods to use the microorganisms and polypeptides of the invention for improved conversion of bio mass to biofuel are provided as well as use of the enzyme in metabolic engineering strategies for producing longer-chain alcohols from sugars using thermophilic, fermentative microorganisms.

The invention relates to a genetically engineered bacterium having an enzyme that converts acetyl-CoA to acetoacetyl-CoA, an enzyme that converts acetoacetyl-CoA to 3-hydroxybutyryl-CoA, and an enzyme that converts 3-hydroxybutyryl-CoA to 3-hydroxybutyrate. The bacterium may also have enzymes to produce other downstream products, such as 3-hydroxybutyryaldehyde, and 1,3-butanediol. Typically, the bacterium is capable of producing these products from a gaseous substrate, such as syngas or an industrial waste gas.

A method for the preparation of 2,4-dihydroxybutyric acid (2,4-DHB) including the successive steps of converting malate, succinyl-CoA and/or glyoxylate into malyl-CoA, converting malyl-CoA previously obtained into malate-4-semialdehyde, and converting malate-4-semialdehyde into 2,4-DHB using a DHB dehydrogenase.

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.

A method for increasing the proportion of an enantiomer of undecavertol in an enantiomeric mixture of undecavertol, a method for stereoselectively synthesising undecavertol, and the products thereof.