TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preparation (Disclosed): The host cell is prepared by standard recombinant DNA or RNA technology. Preferred Host: The host cell comprises an endogenous nucleic acid encoding alcohol dehydrogenase. The host cell is modified such that expression of alcohol dehydrogenase is attenuated relative to the level of expression in a non-modified cell. The host cell further comprises a recombinant nucleic acid encoding naturally secreted protein, where the secreted protein is fused to at least one of the one or more biomass polymer-degrading enzymes. The naturally secreted protein is OsmY from Escherichia coli. Preferred Protein: The crotonase is crt from Clostridium acetobutylicum, butyryl-coA dehydrogenase is bcd from C.acetobutylicum, electron transport flavoprotein B is etfB from C.acetobutylicum, electron transport flavoprotein A is etfA from C.acetobutylicum, 3-hydroxybutyryl-coA dehydrogenase is hbd from C.acetobutylicum, acetyl-coA acetyltransferase is atoB from E.coli, and aldehyde/alcohol dehydrogenase is adhE2 from C.acetobutylicum. The one or more biomass polymer-degrading enzymes are cellulase and beta -glucosidase or endoxylanase and xylobiosidase. EXAMPLE - Cellulase gene was amplified from synthetic DNA and digested with restriction enzymes. The digested product was ligated into plasmid pGB012. Crotonase (crt) gene was amplified from Clostridium acetobutylicum and ligated into plasmid pBMO49 and plasmid pbutanol was produced and then Escherichia coli strain DH1 adhE was constructed. The above plasmids were inserted into the E.coli strain. The engineered E.coli cells were then grown on plant biomass (switchgrass) treated with ionic liquid (IL) containing 1-ethyl-3-methylimidazolium acetate, induced by addition of isopropylthio- beta -galactoside (IPTG), sealed with parafilm creating microaerobic environment, and incubated at 30 degrees C for 96 hours. After incubation, the engineered E.coli cells yielded 28 plus minus 5 mg/L butanol from defined rich medium containing 3.3 weight/volume% of IL-treated switchgrass as the main carbon source.