A NADPH dependent xylose reductase, key enzyme for reducing xylose into xylitol, was isolated from thermotolerant yeast Kluyveromyces sp. IIPE453 and characterized in detail. Purified enzyme (37 KDa) demonstrated maximum activity in pH 6.5 and 45 degrees C temperature. Molecular docking study of in silico protein model revealed a set of polar amino acid residues involved in catalytic mechanism. (C) 2015 Elsevier Ltd. All rights reserved.