Provided is a method of producing a product by culturing a carboxydotrophic acetogenic bacterium with a disrupting mutation in a lactate dehydrogenase enzyme in the presence of a substrate comprising CO, CO.sub.2, and/or H.sub.2. Preferably, the disrupting mutation reduces or eliminates the expression or activity of the enzyme such that the bacterium produces a reduced amount of lactate or no lactate.

A fermentation method includes steps of forming a broth having yeast, water and sugar; and contacting a foam control agent with the broth, a foam formed on the broth or both, wherein the foam control agent has structure (I) wherein R is a linear or branched alkyl group containing from 4 to 18 carbon atoms, m is from 1 to 10, n is from 9 to 15, o is from 15 to 25, and o/n is from 1.00 to 2.00.

A fermentation method includes steps of forming a broth having yeast, water and sugar; and contacting a foam control agent with the broth, a foam formed on the broth or both, wherein the foam control agent has structure (I) wherein R is a linear or branched alkyl group containing from 4 to 18 carbon atoms, m is from 1 to 10, n is from 9 to 15, o is from 15 to 25, and o/n is from 1.00 to 2.00.

The present disclosure provides novel bacterial strains with altered expression or start codon modification of one or more RNA degradation/processing genes. The RNA degradation genes of the present disclosure are controlled by heterologous promoters. The present disclosure further describes methods for generating microbial strains comprising heterologous promoter sequences operably linked to RNA degradation/processing genes.

The present disclosure provides novel bacterial strains with altered expression or start codon modification of one or more RNA degradation/processing genes. The RNA degradation genes of the present disclosure are controlled by heterologous promoters. The present disclosure further describes methods for generating microbial strains comprising heterologous promoter sequences operably linked to RNA degradation/processing genes.

Yeast cells are genetically modified to disrupt a native metabolic pathway from dihydroxyacetone to glycerol. In certain aspects, the yeast cell is of the genera Kluyveromyces, Candida or Issatchenkia. In other aspects, the yeast cell is capable of producing at least one organic acid, such as lactate. The yeast cells produce significantly less glycerol than the wild-type strains, and usually produce greater yields of desired fermentation products. Yeast cells of the invention often grow well when cultivated, despite their curtailed glycerol production.

Yeast cells are genetically modified to disrupt a native metabolic pathway from dihydroxyacetone to glycerol. In certain aspects, the yeast cell is of the genera Kluyveromyces, Candida or Issatchenkia. In other aspects, the yeast cell is capable of producing at least one organic acid, such as lactate. The yeast cells produce significantly less glycerol than the wild-type strains, and usually produce greater yields of desired fermentation products. Yeast cells of the invention often grow well when cultivated, despite their curtailed glycerol production.

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

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

Yeast strains are disclosed that are capable of surviving high ethanol concentrations and propagating in high ethanol concentrations. Genes that are involved in ethanol tolerance are disclosed as well.