title: Purification and characterization of a furfural reductase (FFR) from Escherichia coli strain LYO1--an enzyme important in the detoxification of furfural during ethanol production.
abstract: Furfural, an inhibitor of ethanol production from hemicellulose acid hydrolysates, is reductively detoxified to furfuryl alcohol by the ethanologenic bacterium Escherichia coli strain LYO1. Furfural reductase was purified 106-fold from this bacterium to approximately 50% homogeneity. It has a native molecular mass of 135 kDa, determined by gel filtration, and subunit molecular mass of approximately 68 kDa, determined by denaturing gel electrophoresis, indicating the holoenzyme is a dimer of two similar if not identical subunits. The enzyme shows strong activity from pH 4 to 8 (optimum pH 7.0), relatively high temperature tolerance (50-55 degrees C), and an apparent Km and Vmax for furfural of 1.5x10(-4)M and 28.5 micromol/min/mg of protein, respectively. It catalyzes the essentially irreversible reduction of furfural with NADPH, is specific for NADPH as cofactor, and is relatively specific for the reduction of furfural and benzaldehyde; 2-acetylfuran, xylose, and glucose were not reduced, while acetaldehyde was reduced at a rate 25-fold lower than furfural. This is the first description of a furfural reductase which, based upon size and substrate specificity, appears to represent a new type of alcohol-aldehyde oxido-reductase. The conversion of relatively toxic furfural to less toxic furfuryl alcohol suggests a beneficial role for this enzyme in mitigating furfural toxicity encountered during ethanol production from lignocellulosic biomass.
authors.affiliation: University of Florida, Institute of Food and Agricultural Science, Department of Microbiology and Cell Science, P.O. Box 110700, Gainesville, FL 32611-0700, USA.
authors.forename: Tony
authors.initials: T
authors.lastname: Gutiérrez
authors.forename: Lonnie O
authors.initials: LO
authors.lastname: Ingram
authors.forename: James F
authors.initials: JF
authors.lastname: Preston
mesh_terms: D000449:Aldehyde Reductase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D000431:Ethanol / Q000378:metabolism*; D005662:Furaldehyde / Q000378:metabolism*; D010088:Oxidoreductases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D000431:Ethanol; D005662:Furaldehyde; D010088:Oxidoreductases; D000449:Aldehyde Reductase; C511085:furfural reductase, E coli