Abstract: 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.

Abstract: The invention relates to a recombinant host cell having (a) a modification in an endogenous polynucleotide encoding a polypeptide having dual-role hexokinase activity; (b) a heterologous polynucleotide encoding a polypeptide having hexose kinase activity; and optionally (c) a modification in an endogenous polynucleotide encoding a polypeptide having pyruvate decarboxylase activity. Additionally, the invention relates to methods of making and using such recombinant host cells including, for example, methods of increasing glucose consumption, methods of improving redox balance, and/or methods of increasing the production of a product of a pyruvate-utilizing pathway.

Abstract: Provided herein are processes comprising providing a fermentation medium comprising a fermentable carbon source, a recombinant microorganism comprising an engineered butanol biosynthetic pathway, and butanol; contacting said fermentation medium with an extractant composition comprising an effective amount of antioxidant or antioxidant-like compound, whereby at least a portion of the butanol in the fermentation medium partitions into the extractant; recovering at least a portion of the butanol and extractant composition from the fermentation medium; recycling the extractant composition recovered in (c) one or more times in the fermentation medium; optionally adjusting the effective amount of antioxidant or antioxidant-like compound in the extractant composition, whereby the rate of oxidation or effect of oxidized products in the recycled extractant composition is substantially reduced and/or avoided such that the extractant composition may be recycled.

Abstract: The present invention relates to the fermentative production of alcohols including ethanol and butanol, and processes for improving alcohol fermentation employing in situ product removal methods.

Abstract: Methods for the evolution of NADPH specific ketol-acid reductoisomerase enzymes to acquire NADH specificity are provided. Specific mutant ketol-acid reductoisomerase enzymes isolated from Pseudomonas that have undergone co-factor switching to utilize NADH are described.

Abstract: 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.

Abstract: A group of bacterial dihydroxy-acid dehydratases having a [2Fe-2S] cluster was discovered. Bacterial [2Fe-2S] DHADs were expressed as heterologous proteins in bacteria and yeast cells, providing DHAD activity for conversion of 2,3-dihydroxyisovalerate to ?-ketoisovalerate or 2,3-dihydroxymethylvalerate to ?-ketomethylvalerate. Isobutanol and other compounds may be synthesized in pathways that include bacterial [2Fe-2S] DHAD activity.

Abstract: Bacteria that are not natural butanol producers were found to have increased tolerance to butanol when the membrane content of unsaturated trans fatty acids was increased. Feeding cells with unsaturated trans fatty acids increased their concentration in the membrane, which may also be accomplished by expressing a fatty acid cistrans isomerase.

Abstract: The present invention is related to a recombinant host cell, in particular a yeast cell, comprising a dihydroxy-acid dehydratase polypeptide. The invention is also related to a recombinant host cell having increased specific activity of the dihydroxy-acid dehydratase polypeptide as a result of increased expression of the polypeptide, modulation of the Fe—S cluster biosynthesis of the cell, or a combination thereof. The present invention also includes methods of using the host cells, as well as, methods for identifying polypeptides that increase the flux in an Fe—S cluster biosynthesis pathway in a host cell.

Abstract: The present invention is related to a recombinant host cell, in particular a yeast cell, comprising a dihydroxy-acid dehydratase polypeptide. The invention is also related to a recombinant host cell having increased specific activity of the dihydroxy-acid dehydratase polypeptide as a result of increased expression of the polypeptide, modulation of the Fe—S cluster biosynthesis of the cell, or a combination thereof. The present invention also includes methods of using the host cells, as well as, methods for identifying polypeptides that increase the flux in an Fe—S cluster biosynthesis pathway in a host cell.

Abstract: Provided herein are recombinant yeast host cells and methods for their use for production of isobutanol. Yeast host cells provided comprise an isobutanol biosynthetic pathway and at least one of reduced or eliminated aldehyde dehydrogenase activity, reduced or eliminated acetolactate reductase activity; or a heterologous polynucleotide encoding a polypeptide having ketol-acid reductoisomerase activity.

Abstract: Provided herein are recombinant yeast host cells and methods for their use for production of isobutanol. Yeast host cells provided comprise an isobutanol biosynthetic pathway and at least one of reduced or eliminated aldehyde dehydrogenase activity, reduced or eliminated acetolactate reductase activity; or a heterologous polynucleotide encoding a polypeptide having ketol-acid reductoisomerase activity.

Abstract: 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.

Abstract: A group of bacterial dihydroxy-acid dehydratases having a [2Fe-2S] cluster was discovered. Bacterial [2Fe-2S] DHADs were expressed as heterologous proteins in bacteria and yeast cells, providing DHAD activity for conversion of 2,3-dihydroxyisovalerate to ?-ketoisovalerate or 2,3-dihydroxymethylvalerate to ?-ketomethylvalerate. Isobutanol and other compounds may be synthesized in pathways that include bacterial [2Fe-2S] DHAD activity.

Abstract: Lactic acid bacterial (LAB) cells were modified such that they have a specific activity of dihydroxy-acid dehydratase enzyme activity that is increased to about 0.1 ?mol min?1 mg?1. LAB cells with even higher activities of 0.2 to 0.6 ?mol min?1 mg?1 of DHAD activity were obtained. These modified cells may be used to produce isobutanol when additional isobutanol biosynthetic pathway enzymes are expressed.

Abstract: The invention relates to a recombinant host cell having (a) a modification in an endogenous polynucleotide encoding a polypeptide having dual-role hexokinase activity; (b) a heterologous polynucleotide encoding a polypeptide having hexose kinase activity; and optionally (c) a modification in an endogenous polynucleotide encoding a polypeptide having pyruvate decarboxylase activity. Additionally, the invention relates to methods of making and using such recombinant host cells including, for example, methods of increasing glucose consumption, methods of improving redox balance, and/or methods of increasing the production of a product of a pyruvate-utilizing pathway.

Abstract: The present invention relates to processes and systems for the production of fermentative alcohols such as ethanol and butanol. The present invention also provides methods for separating feed stream components for improved biomass processing and productivity.

Abstract: Methods for the evolution of NADPH specific ketol-add reductoisomerase enzymes to acquire NADH specificity are provided. Specific mutant ketol-acid reductoisomerase enzymes isolated from Pseudomonas that have undergone co-factor switching to utilize NADH are described.

Abstract: Increasing tolerance to butanol in yeast has been accomplished by decreasing activity of Pdr5p encoded by an endogenous PDR5 gene. A deletion mutation of the PDR5 gene led to improved growth yield in the presence of butanol. Yeast cells with reduced Pdr5p activity, or other multidrug resistance ATP-binding cassette transporter protein activity encoded by CDR1 or BFR1, and a butanol biosynthetic pathway may be used for improved butanol production.

Abstract: A method and system for efficiently producing a fermentative product alcohol such as butanol utilizing in situ product extraction are provided. The efficiency is obtained through separating undissolved solids after liquefying a given feedstock to create a feedstock and prior to fermentation, for example, through centrifugation. Removal of the undissolved solids avoids problems associated with having the undissolved solids present during in situ production extraction, and thereby increases the efficiency of the alcohol production.