A new species of an anaerobic thermophilic cellulolytic and xylano lytic bacterium is disclosed. One particular strain of this new species has been deposited with the ATCC under Deposit No. PTA-10114. It is also provided a method for isolating, culturing and utilizing this novel bacterium for the conversion of biomass to bioconversion products, such as ethanol.
 The United States government may have certain rights in the present invention as research relevant to its development was funded by a grant DE-AC05-00OR22725 from the BioEnergy Science Center (BESC), a U.S. Department of Energy (DOE) Bioenergy Research Center supported by the Office of Biological and Environmental Research in the DOE Office of Science and by Mascoma Corp.