Abstract: The present invention provides recombinant mircoorganisms comprising an isobutanol producing metabolic pathway and methods of using said recombinant microorganisms to produce isobutanol. In various aspects of the invention, the recombinant microorganisms may comprise a modification resulting in the reduction of pyruvate decarboxylase and/or glycerol-3-phosphate dehydrogenase activity. In various embodiments described herein, the recombinant microorganisms may be microorganisms of the Saccharomyces clade, Crabtree-negative yeast microorganisms, Crabtree-positive yeast microorganisms, post-WGD (whole genome duplication) yeast microorganisms, pre-WGD (whole genome duplication) yeast microorganisms, and non-fermenting yeast microorganisms.

Abstract: There are disclosed metabolically-engineered yeast and methods of producing n-butanol. In an embodiment, metabolically-engineered yeast is capable of metabolizing a carbon source to produce n-butanol, at least one pathway produces increased cytosolic acetyl-CoA relative to cytosolic acetyl-CoA produced by a wild-type yeast, and at least one heterologous gene encodes and expresses at least one enzyme for a metabolic pathway capable of utilizing NADH to convert acetyl-CoA to n-butanol. In another embodiment, a method of producing n-butanol includes (a) providing metabolically-engineered yeast capable of metabolizing a carbon source to produce n-butanol, at least one pathway produces increased cytosolic acetyl-CoA relative to cytosolic acetyl-CoA produced by a wild-type yeast, and at least one heterologous gene encodes and expresses at least one enzyme for a metabolic pathway utilizing NADH to convert acetyl-CoA to n-butanol; and (b) culturing the yeast to produce n-butanol. Other embodiments are also disclosed.

Abstract: There is disclosed a method of producing isobutanol. In an embodiment, the method includes providing a microorganism transformed with an isobutanol producing pathway containing at least one exogenous gene. The microorganism is selected to produce isobutanol from a carbon source at a yield of at least 10 percent theoretical. The method includes cultivating the microorganism in a culture medium containing a feedstock providing the carbon source, until isobutanol is produced. The method includes recovering the isobutanol. In one embodiment, the microorganism is a yeast with a Crabtree-negative phenotype. In another embodiment, the microorganism is a yeast microorganism with a Crabtree-positive phenotype. There is disclosed a microorganism for producing isobutanol. In an embodiment, the microorganism includes an isobutanol producing pathway containing at least one exogenous gene, and is selected to produce a recoverable quantity of isobutanol from a carbon source at a yield of at least 10 percent theoretical.