Isolation and characterization of a β-glucosidase from Penicillium decumbens and improving hydrolysis of corncob residue by using it as cellulase supplementation

A β-glucosidase from Penicillium decumbens was purified and characterized. The enzyme presented as a single band of 120 kDa on SDS-PAGE, showed optimal temperature of 65-70 °C and optimal pH of 4.5-5.0. The β-glucosidase showed relatively higher affinity to pNPG and the highest affinity to salicin with the Km value as 0.0064 and 0.0188 mM, respectively. The gene coding for it was obtained with an ORF 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.