Purification and characterization of an acidophilic cellulase from Pleurotus ostreatus and its potential for agrowastes valorization

Cellulase is a valuable enzyme with numerous industrial applications. Its production from different sources has formed a major focus for research. In this study, an extracellular acidophilic cellulase was isolated and purified from the edible mushroom Pleurotus ostreatus. The enzyme was isolated from the culture filtrate of the mushroom mycelia grown under submerged fermentation. The enzyme was purified to homogeneity with a recovery of 17.9%, purification fold of 17.4 and molecular weight of 58 kDa. Optimum pH and temperature of the purified cellulase from Pleurotus ostreatus was 4.0 and 55 °C respectively. The Km and Vmax values of the purified enzyme were 63 μM and 1.90 µmol/min respectively using Carboxymethyl cellulose (CMC) as substrate. The enzyme was activated by Mg2+, Zn2+, Ca2+, Co2+ and Mn2+ while Sodium dodecyl sulphate (SDS), ethylenediaminetetraacetic acid (EDTA), β-mercaptoethanol, urea, Fe2+, Cu2+ and K+ were found to be inhibitors of the enzyme. The purified cellulase was able to hydrolyze selected agrowastes. The findings of this study have shown that Pleurotus ostreatus may be a promising renewable source of cellulase which could be explored for biomass degradation and other industrial applications.