Cellulolytic and hemicellulolytic enzymes of sclerotium rolfsii: Optimization of the culture medium and enzymatic hydrolysis of lignocellulosic material

Abstract

A culture medium for a wild strain of Sclerotium rolfsii was optimized with respect to cellulase formation by employment of response surface methodology. The medium components that were found to show the strongest influence on cellulase production were selected for the optimization process, and included α-cellulose and peptone from meat. The optimal concentrations for these two factors were determined in an experiment planned according to an orthogonal central composite design, in which a mathematical model was fitted to the experimental data. The optimal concentrations for the two variables cellulose and peptone, as predicted from the model equation, were 37.6 g/liter and 80.2 g/liter, respectively. The optima, as predicted by the model, were verified in shaken flask experiments. When S. rolfsii was cultivated on the optimized medium, a maximum cellulase activity of 5.72±0.39 FPU/ml was obtained. Additionally, high levels of β-glucosidase and various hemicellulolytic enzyme activities, including xylanase and mannanase, were produced. A crude culture filtrate of S. rolfsii was used for the hydrolysis of various lignocellulosic materials, including agricultural residues.