A beta-glucosidase from Penicillium decumbens was purified and characterized. The enzyme presented as a single band of 120 kDa on SOS-PAGE, showed optimal temperature of 65-70 degrees C and optimal pH of 4.5-5.0. The beta-glucosidase showed relatively higher affinity to pNPG and the highest affinity to salicin with the K-m value as 0.0064 and 0.0188 mM, respectively. The gene coding for it was obtained with an ORE of 2586 bp coding for 861 amino acids belonging to glycoside hydrolases family 3. The purified enzyme could improve the saccharifying ability of cellulose when it was added to the cellulase systems of Trichoderma reesei QM 9414. The several properties of it, including its pH and temperature optima, the high affinity to substrates and high specific activity, make it has great potential to be utilized as supplementation in conversion of corncob residue and other lignocellulosic biomass into simple sugars. Crown Copyright (C) 2010 Published by Elsevier Inc. All rights reserved.