Studies on cellulase production by immobilized cells and characteristics of cellulase

Immobilized cells were prepared through embedment of Trichoderma aureoviride with calcium alginate. The suitable culture conditions were sodium alginate 50 g/L, initial pH value of the substrate 4.0-4.5 and using filter paper pulp as carbon source of the substrate. The enzymatic activity of the immobilized cells was improved when concentration of calcium dichloride was 20 g/L, initial pH value of the substrate was 4.5, concentration of sodium alginate was 50 g/L using filter paper pulp as carbon source of the substrate. Addition of the surfactant Twin-80 could further increase enzymatic activity. Three endoglucanases and two β-glucosidases from the fungi were separated and purified to electrophoretic homogeneity through processes of (NH₄)₂SO₂ fractional precipitation, Sephadex G-100 gel chromatography and DEAE Sephadex A-50 ion exchange chromatography. They were designated as EG I, EG II, EG III, BG I and BG II, with relative molecular weights (M_r) of 62300, 71900, 52600, 85300 and 78300 by SDS-PAGE, and isoelectric points of 5.4, 4.8, 5.0, 5.6 and 5.8, respectively.