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.

Abstract: Methods for producing a biofuel precursor are provided. Also provided are biocatalysts that convert a feedstock to a biofuel precursor.

Abstract: This invention is directed to methods for recovery of C3-C6 alcohols from dilute aqueous solutions, such as fermentation broths. Such methods provide improved volumetric productivity for the fermentation and allows recovery of the alcohol. Such methods also allow for reduced energy use in the production and drying of spent fermentation broth due to increased effective concentration of the alcohol product by the simultaneous fermentation and recovery process which increases the quantity of alcohol produced and recovered per quantity of fermentation broth dried. Thus, the invention allows for production and recovery of C3-C6 alcohols at low capital and reduced operating costs.

Abstract: A recombinant microorganism expressing at least a heterologous enzyme of an NADH-dependent pathway for conversion of a carbon source to n-butanol, metabolic intermediate and/or a derivative thereof and capable of producing n-butanol, a metabolic intermediate and/or a derivative thereof at a high yield and related methods. The recombinant microorganism engineered to inactivate a native enzyme of one or more pathways that compete with NADH-dependent heterologous pathway, and/or to balance the NADH-dependent heterologous pathway with respect to NADH production and consumption.

Abstract: In an embodiment, there is disclosed a recombinant microbial host cell having each of the DNA molecules encoding a polypeptide or group of polypeptides that catalyze the conversion: (i) Acetyl-CoA to Acetate and CoA ??(conversion 1) (ii) Acetyl-CoA to Acetoacetyl-CoA and CoA ??(conversion 2) (iii) Acetoacetyl-CoA and Acetate to Acetoacetate and Acetyl-CoA ??(conversion 3.1) (iv) Acetoacetate to Acetone and CO2 ??(conversion 4) (v) Acetone and NAD(P)H and H+ to Isopropanol and NAD(P)+ ??(conversion 5) wherein at least one DNA molecule is heterologous to the microbial host cell and wherein the microbial host cell produces isopropanol. In another embodiment, a method is disclosed for the production of isopropanol including providing a recombinant microbial host cell, the host cell of (i) with a fermentable carbon substrate in a fermentation medium under conditions whereby isopropanol is produced, and recovering the isopropanol.