Comparative studies on glucanases and β-glucosidase activities of Pleurotus ostreatus and P. pulmonarius in solid state fermentation

Abstract

Agricultural wastes constitute major environmental problem. However, these wastes can be used as substrates for the production of enzymes such as cellulases by filamentous fungi including Pleurotus species. This present investigation was therefore aimed at screening Pleurotus ostreatus DBUI 14 and P. pulmonarius DBUI002 for glucanases and β-glucosidase using rice bran, corn cob and sawdust as substrates. Both P. ostreatus DBUI14 and P. pulmonarius DBUI002 cultivated on pretreated rice bran, corn cob and sawdust were screened for cellulolytic enzymes under solid state fermentation (SSF) for a period of 15 days using standard methods. The protein contents were determined using the method of Lowry. The results showed that lowest activities of these enzymes by Pleurotus spp occurred on the third and fifteenth days while the highest activities occurred on the ninth day of fermentation. The highest endoglucanase as well as lowest exoglucanase activities were obtained from Pleurotus pulmonarius DBUI002cultivated on corn cob (PPCC). Pleurotus ostreatus DBUI 14 cultivated on corn cob (POCC) had the lowest endoglucanase but highest exoglucanase activity when grown on rice bran (PORB). Moreover, lowest β-glucosidase activity was obtained from POCC while PPCC and PORB had the highest β-glucosidase activities. Pleurotus pulmonarius cultivated on corn cob and P. ostreatus cultivated on rice bran could be harnessed in the commercial production of endoglucanase and exoglucanase. In addition, both Pleurotus ostreatus DBUI 14 strain and P. pulmonarius DBUI002 could be harnessed in synthesis of β-glucosidase.