Abstract: The present invention provides for the manipulation of cofactor usage in a recombinant host cell to increase the formation of desirable products. In some embodiments, the invention provides for a recombinant microorganism comprising a mutation in one or more native enzymes such that their cofactor specificity is altered in such a way that overall cofactor usage in the cell is balanced for a specified pathway and there is an increase in a specific product formation within the cell. In some embodiments, endogenous enzymes are replaced by enzymes with an alternate cofactor specificity from a different species.

Abstract: The present invention provides for the manipulation of carbon flux in a recombinant host cell to increase the formation of desirable products. The invention relates to cellulose-digesting organisms that have been genetically modified to allow the production of ethanol at a high yield by redirecting carbon flux at key steps of central metabolism.

Abstract: One aspect of the invention relates to industrial bioconversion of the xylose portion of biomass materials into fuels and chemicals. Another aspect of the invention relates to industrial bioconversion of the xylan portion of biomass materials into fuels and chemicals. In one embodiment, the invention is directed to the bacterium Clostridium thermocellum, a highly cellulolytic organism that has much potential as a biocatalyst in a consolidated bioprocess configuration. In some embodiments, the invention is a genetic modification that confers the ability to ferment xylose to C. thermocellum and the strains created with this modification. In some embodiments, the genetic modification is composed of two genes contained in an operon from T. saccharolyticum. The genes express proteins with xylose isomerase (XI) and xylulokinase activites (XK). In other embodiments, the invention relates to a recombinant Clostridium thermocellum host cell capable of fermenting xylan.

Abstract: Thermophilic gram-positive anaerobic host cells, for example Thermoanaerobacterium saccharolyticum (“T sacch”), express heterologous biomass degrading enzymes, such as cellulases, and are able to produce useful fermentation products from cellulose. Useful fermentation products include, for example, ethanol, acetic acid, lactic acid or CO2. In order to provide maximum expression and activity levels, biomass degrading enzymes can be expressed from codon-optimized nucleotide sequences, can be expressed under the control of a high-efficiency promoter, and/or can be fused to a signal peptide. In addition, the host cell, for example, a T sacch host cell, can be genetically altered to further improve ethanol production, for example by disrupting the production of organic products other than ethanol.