Abstract: Methods of identifying genes conferring ethanol tolerance in yeasts, genes that confer ethanol tolerance, and mutant strains used to identify such genes are described. A gene herein designated HpETT1 was isolated from the yeast Hansenula polymorpha. Expression of HpETT1 in an ethanol sensitive mutant H. polymorpha strain designated 7E complimented ethanol sensitivity of the mutant. When multiple copies of the HpETT1 were integrated into the genome and overexpressed, the transformed strain demonstrated approximately 10-fold greater resistance to ethanol and resistance to the protein misfolding agent AZC. Expression of HpETT1 also increased ethanol tolerance in Saccharomyces cerevisiae. HpEtt1 has 39% sequence identity to a previously identified protein from S. cerevisiae denoted MPE1, however, the MPE1 gene does not confer ethanol resistance to the 7E mutant.

Abstract: Described herein are new approaches for the selection of S. cerevisiae strains with increased ethanol production from hydrolyzed starch derived sugars. An industrial production strain of Saccharomyces cerevisiae AS400 was subjected to positive selection of mutants resistant to toxic concentrations of oxythiamine, trehalose, 3-bromopyruvate, glyoxylic acid, and glucosamine. The selected mutants are characterized by 5-8% increase in ethanol yield (g g?1 of consumed glucose) as compared to the parental industrial ethanol-producing strain. A multiple-step selection approach that consisted of the sequential selection using glyoxylic acid, glucosamine and bromopyruvate as selective agents resulted in a 12% increase in ethanol yield during fermentation on industrial media. These results indicate that the selection methods provided herein are useful for producing a variety of strains that are promising candidates for industrial ethanol production.

Abstract: Described herein are new approaches for the selection of S. cerevisiae strains with increased ethanol production from hydrolyzed starch derived sugars. An industrial production strain of Saccharomyces cerevisiae AS400 was subjected to positive selection of mutants resistant to toxic concentrations of oxythiamine, trehalose, 3-bromopyruvate, glyoxylic acid, and glucosamine. The selected mutants are characterized by 5-8% increase in ethanol yield (g g?1 of consumed glucose) as compared to the parental industrial ethanol-producing strain. A multiple-step selection approach that consisted of the sequential selection using glyoxylic acid, glucosamine and bromopyruvate as selective agents resulted in a 12% increase in ethanol yield during fermentation on industrial media. These results indicate that the selection methods provided herein are useful for producing a variety of strains that are promising candidates for industrial ethanol production.

Abstract: Described herein is a method to increase ethanol yield during alcoholic fermentation by expression a truncated versions of the Saccharomyces cerevisiae PHO8 gene coding for vacuolar or cytosolic form of alkaline phosphatase, which expression lowers biomass accumulation while diverting greater carbon to ethanol production. Also described are as nucleic acid sequences and vectors for expression of the PHO8 gene and strains carrying the same. Strains containing intact PHO8 gene encoding vacuolar form of alkaline phosphatase, had slightly lower intracellular ATP levels with insignificant changes in biomass accumulation and up to 13% increase in ethanol production.

Abstract: Methods of identifying genes conferring ethanol tolerance in yeasts, genes that confer ethanol tolerance, and mutant strains used to identify such genes are described. A gene herein designated HpETT1 was isolated from the yeast Hansenula polymorpha. Expression of HpETT1 in an ethanol sensitive mutant H. polymorpha strain designated 7E complimented ethanol sensitivity of the mutant. When multiple copies of the HpETT1 were integrated into the genome and overexpressed, the transformed strain demonstrated approximately 10-fold greater resistance to ethanol and resistance to the protein misfolding agent AZC. Expression of HpETT1 also increased ethanol tolerance in Saccharomyces cerevisiae. HpEtt1 has 39% sequence identity to a previously identified protein from S. cerevisiae denoted MPE1, however, the MPE1 gene does not confer ethanol resistance to the 7E mutant.

Abstract: A truncated version of Saccharomyces cerevisiae IVL2 gene encoding a cytosolic form of acetolactate synthase was cloned into an expression cassette under control of a strong constitutive alcohol dehydrogenase (ADH1) promoter. The plasmid was introduced into the S. cerevisiae strain and the recombinant strain was tested for ability to overproduce glycerol under anaerobic conditions. It was shown that the recombinant strain was characterized by increased glycerol production and decreased ethanol production under anaerobic conditions.

Abstract: Methods of identifying genes conferring ethanol tolerance in yeasts, genes that confer ethanol tolerance, and mutant strains used to identify such genes are described. A gene herein designated HpETT1 was isolated from the yeast Hansenula polymorpha. Expression of HpETT1 in an ethanol sensitive mutant H. polymorpha strain designated 7E complimented ethanol sensitivity of the mutant. When multiple copies of the HpETT1 were integrated into the genome and overexpressed, the transformed strain demonstrated approximately 10-fold greater resistance to ethanol and resistance to the protein misfolding agent AZC. Expression of HpETT1 also increased ethanol tolerance in Saccharomyces cerevisiae. HpEtt1 has 39% sequence identity to a previously identified protein from S. cerevisiae denoted MPE1, however, the MPE1 gene does not confer ethanol resistance to the 7E mutant.

Abstract: Genes SWA2 and GAM1 from the yeast, Schwanniomyces occidentalis, encoding ?-amylase and glucoamylase, respectively, were cloned and expressed in H. polymorpha. The expression was achieved by integration of the SWA2 and GAM1 genes into the chromosome of H. polymorpha under operably linked to a strong constitutive promoter of the H. polymorpha-glyceraldehyde-3-phosphate dehydrogenase gene (HpGAP. Resulting transformants acquired the ability to grow on a minimal medium containing soluble starch as a sole carbon source and can produce Ethanol at high-temperature fermentation from starch up to 10 g/L. A XYN2 gene encoding endoxylanase was obtained from the fungus Trichoderma resee, and a xlnD gene coding for ?-xylosidase was obtained from the fungus Aspergillus niger. Co-expression of these genes was also achieved by integration into the H. polymorpha chromosome under control of the HpGAP promoter.

Abstract: Recombinant genetic constructs and strains of H. polymorpha having significantly increased ethanol productivity with a simultaneous decreased production of xylitol during high-temperature xylose fermentation are disclosed. The constructs include a H. polymorpha XYL1 gene encoding xylose reductase mutated to decrease affinity of the enzyme toward NADPH. The modified version of XYL1 gene under control of a strong constitutive HpGAP promoter was overexpressed in a ?xyl1 background. A recombinant H. polymorpha strain overexpressing the mutated enzyme together with native xylitol dehydrogenase and xylulokinase in the ?xyl1 background was also constructed. Xylose consumption, ethanol and xylitol production by the constructed strain were evaluated during high-temperature xylose fermentation (48° C.). A significant increase in ethanol productivity (up to 7.4 times) was shown in the recombinant strain as compared with the wild type strain.

Abstract: Described herein is a method to increase ethanol yield during alcoholic fermentation by expression a truncated versions of the Saccharomyces cerevisiae PHO8 gene coding for vacuolar or cytosolic form of alkaline phosphatase, which expression lowers biomass accumulation while diverting greater carbon to ethanol production. Also described are as nucleic acid sequences and vectors for expression of the PHO8 gene and strains carrying the same. Strains containing intact PHO8 gene encoding vacuolar form of alkaline phosphatase, had slightly lower intracellular ATP levels with insignificant changes in biomass accumulation and up to 13% increase in ethanol production.

Abstract: Methods of identifying genes conferring ethanol tolerance in yeasts, genes that confer ethanol tolerance, and mutant strains used to identify such genes are described. A gene herein designated HpETT1 was isolated from the yeast Hansenula polymorpha. Expression of HpETT1 in an ethanol sensitive mutant H. polymorpha strain designated 7E complimented ethanol sensitivity of the mutant. When multiple copies of the HpETT1 were integrated into the genome and overexpressed, the transformed strain demonstrated approximately 10-fold greater resistance to ethanol and resistance to the protein misfolding agent AZC. Expression of HpETT1 also increased ethanol tolerance in Saccharomyces cerevisiae. HpEtt1 has 39% sequence identity to a previously identified protein from S. cerevisiae denoted MPE1, however, the MPE1 gene does not confer ethanol resistance to the 7E mutant.

Abstract: Methods and compositions for the production of ethanol from lignocellulosic starting materials are provided herein. Embodiments provide yeast cells of the genus H. polymorpha with one or more modifications, including, for example, an inactive acid trehalase gene, overexpression of xylulokinase, and/or overexpression of heat-shock protein 104.

Abstract: A new approach for increase of ethanol yield during alcoholic fermentation via decrease of biomass accumulation by using ATP degrading enzymes is described. The part of the Saccharomyces cerevisiae SSB1 gene coding for cytosolic ATPase domain of ribosome associated chaperon cloned into expression cassette under control of the glycerol-3-phosphate dehydrogenase gene (GPD1) promoter was introduced into the S. cerevisiae BY4742 strain. The recombinant strains were tested for their ability to grow and produce ethanol during glucose anaerobic and aerobic cultivations. Strains overexpressing ATPase domain of SSB1 possessed decreased concentration of intracellular ATP. They accumulated elevated amounts of ethanol and were characterized by decreased biomass accumulation as compared to the wild-type strain under both anaerobic and aerobic conditions. Similarly, the apyrase gene apy from E. coli encoding ATP/ADP hydrolyzing phosphatase and ATPase domain of SSB1 gene of S.

Abstract: Methods and compositions for the production of ethanol from lignocellulosic starting materials are provided herein. Embodiments provide yeast cells of the genus H. polymorpha with one or more modifications, including, for example, an inactive acid trehalase gene, overexpression of xylulokinase, and/or overexpression of heat-shock protein 104.

Abstract: A new approach for increase of ethanol yield during alcoholic fermentation via decrease of biomass accumulation by using ATP degrading enzymes is described. The part of the Saccharomyces cerevisiae SSB1 gene coding for cytosolic ATPase domain of ribosome associated chaperon cloned into expression cassette under control of the glycerol-3-phosphate dehydrogenase gene (GPD1) promoter was introduced into the S. cerevisiae BY4742 strain. The recombinant strains were tested for their ability to grow and produce ethanol during glucose anaerobic and aerobic cultivations. Strains overexpressing ATPase domain of SSB1 possessed decreased concentration of intracellular ATP. They accumulated elevated amounts of ethanol and were characterized by decreased biomass accumulation as compared to the wild-type strain under both anaerobic and aerobic conditions. Similarly, the apyrase gene apy from E. coH encoding ATP/ADP hydrolyzing phosphatase and ATPase domain of SSB1 gene of S.

Abstract: Methods and compositions for the production of ethanol from lignocellulosic starting materials are provided herein. Embodiments of the invention provide methods of manipulating the carbon flux of a host cell transformed with plasmids of the invention. Plasmids of the invention may include nucleotides that encode pyruvate decarboxylase. In one embodiment, a strain of the thermotolerant yeast Hansenula polymorpha that has been transformed with plasmids and polynucleotides of the invention is provided.

Abstract: Recombinant genetic constructs and strains of H. polymorpha having significantly increased ethanol productivity with a simultaneous decreased production of xylitol during high-temperature xylose fermentation are disclosed. The constructs include a H. polymorpha XYL1 gene encoding xylose reductase mutated to decrease affinity of the enzyme toward NADPH. The modified version of XYL1 gene under control of a strong constitutive HpGAP promoter was overexpressed in a ?xyll background. A recombinant H. polymorpha strain overexpressing the mutated enzyme together with native xylitol dehydrogenase and xylulokinase in the ?xyll background was also constructed. Xylose consumption, ethanol and xylitol production by the constructed strain were evaluated during high-temperature xylose fermentation (48° C.). A significant increase in ethanol productivity (up to 7.4 times) was shown in the recombinant strain as compared with the wild type strain.

Abstract: Genes SWA2 and GAMl from the yeast, Schwanniomyces occidentalis, encoding ?-amylase and glucoamylase, respectively, were cloned and expressed in H. polymorpha. The expression was achieved by integration of the SWA2 and GAM1 genes into the chromosome of H. polymorpha under operably linked to a strong constitutive promoter of the H. polymorpha-glyceraldehyde-3-phosphate dehydrogenase gene (HpGAP. Resulting transformants acquired the ability to grow on a minimal medium containing soluble starch as a sole carbon source and can produce Ethanol at high-temperature fermentation from starch up to 10 g/L. A XYN2 gene encoding endoxylanase was obtained from the fungus Trichoderma resee, and a xlnD gene coding for ?-xylosidase was obtained from the fungus Aspergillus niger. Co-expression of these genes was also achieved by integration into the H. polymorpha chromosome under control of the HpGAP promoter.

Abstract: Methods and compositions for the production of ethanol from lignocellulosic starting materials are provided herein. Embodiments provide yeast cells of the genus H. polymorpha with one or more modifications, including, for example, an inactive acid trehalase gene, overexpression of xylulokinase, and/or overexpression of heat-shock protein 104.

Abstract: Methods and compositions for the production of ethanol from lignocellulosic starting materials are provided herein. Embodiments of the invention provide methods of manipulating the carbon flux of a host cell transformed with plasmids of the invention. Plasmids of the invention may include nucleotides that encode pyruvate decarboxylase. In one embodiment, a strain of the thermotolerant yeast Hansenula polymorpha that has been transformed with plasmids and polynucleotides of the invention is provided.