Potentials of Rice Bran and Oil Palm Fibre as Substrate for Exo-Β-Glucanase Production by <i>Penicillium chrysogenum</i>

Abstract

Glucanases are important industrial enzymes that catalyze the hydrolysis of glucan into oligo-saccharides. Commercial β-glucanase are produced from microorganisms such as Penicillium chrysogenum, Aspergillus flavus, Pseudomonas fluorescens etc. The increasing application of glucanases in various industries has called for continuous search for cheaper means of gluca-nase production. This study explores β-glucanase production from Penicillium chrysogenum using rice bran and oil palm fiber as substrates. Fungal isolates of soil samples were charac-terized and screened for exo- β-glucanase activity using modified Czapek-Dox Agar (MCDA). Production of exo-β-glucanase was carried out through submerged fermentation system. Crude enzyme produced was extracted and assayed for enzyme activity and protein concen-tration using standard methods Enzyme purification was carried out using ammonium sulphate precipitation and dialysis methods. The purified enzyme was characterized by measuring the effect of temperature, pH, various salts and inhibitors. The optimal conditions for exo-β-glucanase production were found to be 96 hours of incubation, a pH of 4.5 for rice bran and 5.5 for oil palm fiber, and temperatures of 30°C for rice bran and 35°C for oil palm fiber, with ammonium sulphate and oil palm fiber as the best nitrogen and carbon sources respectively. The enzymes were purified with 80% ammonium sulphate and dialysis tubing, resulting in a 1.09 to 1.50-fold increase in purification. The addition of chloride salts, surfactants, and EDTA impacted the activity of the enzyme. Based on its physiochemical properties, the partially purified enzyme has potential industrial and biotechnological applications, such as in beer production and as an additive in laundry detergents and saccharification.