초록
Extracellular β-glucosidase was produced using coffee pulp as a sole carbon source by Penicillium verrucosum by solid state fermentation and 897.36±59 U/g enzyme activity was obtained. Increase in 2.21-fold of enzyme activity on optimizing the bioprocess parameters by response surface methodology based on central composite rotatable design is illustrated. Maximum production level of 1,991.17 U/g was obtained with optimum values of pH 4.2, moisture 66.8%, and fermentation duration of 56 h.The enzyme was partially purified and the enzyme activity was optimum at 50oC temperature and at pH 6. The metal ions such as Mg2+, Zn2+, Ca2+, K+, detergents, and chelator such as EDTA were effective and further increased the β-glucosidase activity. On application of β-glucosidase for simultaneous saccharifiation and fermentation, 3.3% ethanol was obtained. Thus, this study provides insight on exploitation of P. verrucosum for synthesis of of β-glucosidase using coffee pulp which is available abundantly in coffee processing industries.