Abstract: Described are compositions and methods relating to modified yeast that over-express the glycerol-deficient suppressor, GDS1. The yeast produces an increased amount of ethanol and a deceased amount of acetate compared to parental cells. Such yeast is particularly useful for large-scale ethanol production from starch substrates where acetate in an undesirable end product.

Abstract: Provided herein, inter alia, are compositions comprising oxygen tolerant strains of Megasphaera elsdenii and methods of making and using the same to promote improvement of one or more metrics in an animal, such as increased bodyweight/carcass gain, increased feed intake, decreased feed conversion ratio (FCR), decreased medical costs, decreased transition period, decrease use of antibiotics, and reduced mortality.

Abstract: Described are compositions and methods relating to modified yeast that over-express the glycerol-deficient suppressor, GDS1. The yeast produces an increased amount of ethanol and a deceased amount of acetate compared to parental cells. Such yeast is particularly useful for large-scale ethanol production from starch substrates where acetate in an undesirable end product.

Abstract: Described are compositions and methods relating to yeast having a genetic mutation that results in increased alcohol production and tolerance, including increased ethanol production and increased butanol tolerance. Such yeast is well-suited for use in alcohol and butanol production to increase yields.

Abstract: Disrupting expression of a protein encoded by the region of the Zymomonas genome called ZMO0353 in the genomic sequence of the ZM4 strain was found to improve the use of xylose in a recombinant xylose utilizing Zymomonas cell. In addition, utilization of both xylose and arabinose was improved in a xylose and arabinose utilizing Zymomonas cell with this disruption, and increased ethanol production was achieved.

Abstract: Disrupting expression of a protein encoded by the region of the Zymomonas genome called ZMO0353 in the genomic sequence of the ZM4 strain was found to improve the use of xylose in a recombinant xylose utilizing Zymomonas cell. In addition, utilization of both xylose and arabinose was improved in a xylose and arabinose utilizing Zymomonas cell with this disruption, and increased ethanol production was achieved.

Abstract: The endogenous pnp gene encoding polynucleotide phosphorylase in the Zymomonas genome was identified as a target for modification to provide improved xylose utilizing cells for ethanol production. The cells are in addition genetically modified to have increased expression of ribose-5-phosphate isomerase (RPI) activity, as compared to cells without this genetic modification, and are not limited in xylose isomerase activity in the absence of the pnp modification.

Abstract: Zymomonas is unable to synthesize pantothenic acid and requires this essential vitamin in growth medium. Zymomonas strains transformed with an operon for expression of 2-dehydropantoate reductase and aspartate 1-decarboxylase were able to grow in medium lacking pantothenic acid. These strains may be used for ethanol production without pantothenic acid supplementation in seed culture and fermentation media.

Abstract: Expression of a xylose isomerase in a yeast cell that expresses the chaperonins GroES and GroEL was found to result in enzymatically active xylose isomerase, while there is little to no activity with expression of the bacterial xylose isomerase in a yeast cell lacking GroES and GroEL. A yeast cell expressing xylose isomerase activity, and a complete xylose utilization pathway, provides a yeast cell that can produce a target compound, such as ethanol, butanol, or 1,3-propanediol, using xylose derived from lignocellulosic biomass as a carbon source.

Abstract: Xylose-utilizing Zymomonas strains studied were found to accumulate ribulose when grown in xylose-containing media. Engineering these strains to increase ribose-5-phosphate isomerase activity led to reduced ribulose accumulation, improved growth, improved xylose utilization, and increased ethanol production.

Abstract: Zymomonas expressing xylose isomerase from A. missouriensis was found to have improved xylose utilization, growth, and ethanol production when grown in media containing xylose. Xylose isomerases related to that of A. missouriensis were identified structurally through molecular phylogenetic and Profile Hidden Markov Model analyses, providing xylose isomerases that may be used to improve xylose utilization.

Abstract: Zymomonas is unable to synthesize pantothenic acid and requires this essential vitamin in growth medium. Zymomonas strains transformed with an operon for expression of 2-dehydropantoate reductase and aspartate 1-decarboxylase were able to grow in medium lacking pantothenic acid. These strains may be used for ethanol production without pantothenic acid supplementation in seed culture and fermentation media.

Abstract: Xylose-utilizing Zymomonas strains studied were found to accumulate ribulose when grown in xylose-containing media. Engineering these strains to increase ribose-5-phosphate isomerase activity led to reduced ribulose accumulation, improved growth, improved xylose utilization, and increased ethanol production.

Abstract: Zymomonas expressing xylose isomerase from A. missouriensis was found to have improved xylose utilization, growth, and ethanol production when grown in media containing xylose. Xylose isomerases related to that of A. missouriensis were identified structurally through molecular phylogenetic and Profile Hidden Markov Model analyses, providing xylose isomerases that may be used to improve xylose utilization.

Abstract: Strains of Zymomonas were engineered by introducing a chimeric xylose isomerase gene that contains a mutant promoter of the Z. mobilis glyceraldehyde-3-phosphate dehydrogenase gene. The promoter directs increased expression of xylose isomerase, and when the strain is in addition engineered for expression of xylulokinase, transaldolase and transketolase, improved utilization of xylose is obtained.

Abstract: Identified are mutants of the promoter of the Z. mobilis glyceraldehyde-3-phosphate dehydrogenase gene, which direct improved expression levels of operably linked heterologous nucleic acids. These are high expression promoters useful for expression of chimeric genes in Zymomonas, Zymobacter, and other related bacteria.

Abstract: Through screening of a Zymomonas mutant library the himA gene was found to be involved in the inhibitory effect of acetate on Zymomonas performance. Xylose-utilizing Zymomonas strains further engineered to reduce activity of the himA gene were found to have increased ethanol production in comparison to a parental strain, when cultured in mixed-sugars medium comprising xylose, and, in particular, in the presence of acetate.

Abstract: Through screening of a Zymomonas mutant library the himA gene was found to be involved in the inhibitory effect of acetate on Zymomonas performance. Xylose-utilizing Zymomonas further engineered to reduce activity of the himA gene were found to have increased ethanol production in comparison to a parental strain, when cultured in medium comprising xylose and acetate.

Abstract: Identified are mutants of the promoter of the Z. mobilis glyceraldehyde-3-phosphate dehydrogenase gene, which direct improved expression levels of operably linked heterologous nucleic acids. These are high expression promoters useful for expression of chimeric genes in Zymomonas, Zymobacter, and other related bacteria.

Abstract: Strains of Zymomonas were engineered by introducing a chimeric xylose isomerase gene that contains a mutant promoter of the Z. mobilis glyceraldehyde-3-phosphate dehydrogenase gene. The promoter directs increased expression of xylose isomerase, and when the strain is in addition engineered for expression of xylulokinase, transaldolase and transketolase, improved utilization of xylose is obtained.