Abstract: Disclosed are compositions and methods relating to maltopentaose/maltohexaose-forming ?-amylases. The variant ?-amylases are useful, for example, for starch liquefaction and saccharification, for cleaning starchy stains in laundry, dishwashing, and other applications, for textile processing (e.g., desizing), in animal feed for improving digestibility, and for baking and brewing.

Abstract: Dihydroxy-acid dehydratase (DHAD) variants that display increased DHAD activity are disclosed. Such enzymes can result in increased production of compounds from DHAD requiring biosynthetic pathways. Also disclosed are isolated nucleic acids encoding the DHAD variants, recombinant host cells comprising the isolated nucleic acid molecules, and methods of producing butanol.

Abstract: Bacteria that are not natural butanol producers were found to have increased tolerance to butanol when the saturated fatty acids content in bacterial cell membrane was increased. Methods for increasing the concentration of saturated fatty acids in the membranes of bacteria that are not natural butanol produces are described whereby tolerance of the bacterial cell to butanol is increased. Saturated fatty acids concentration in the bacterial cell membrane increased upon exogenously feeding saturated fatty acids to cells. Bacterial strains useful for production of butanol are described herein having modified unsaturated fatty acid biosynthetic pathway.

Abstract: A high flux of metabolites from pyruvate to 2,3-butanediol in Lactobacillus plantarum was achieved through genetic engineering. Substantial elimination of lactate dehydrogenase activity in the presence of heterologously expressed butanediol dehydrogenase activity led to 2,3 butanediol production that was at least 49% of the total of major pyruvate-derived products.

Abstract: Lactic acid bacterial (LAB) cells were modified such that they have a specific activity of dihydroxy-acid dehydratase enzyme activity that is increased to about 0.1 ?mol min?1 mg?1. LAB cells with even higher activities of 0.2 to 0.6 ?mol min?1 mg?1 of DHAD activity were obtained. These modified cells may be used to produce isobutanol when additional isobutanol biosynthetic pathway enzymes are expressed.

Abstract: Lactic acid bacteria expressing dihydroxyacid dehydratase polypeptides with increased specific activity are disclosed. The lactic acid bacteria comprise recombinant genes encoding iron-sulfur cluster forming proteins.