Isolation and characterization of 1,4-β-glucan 4-glucanohydrolases (EC 3.2.1.4) from a technical Trichoderma viride cellulase

The following enzyme activities were detected in a Trichoderma viride cellulase (Röhm 2230 B): 1,4-β-d-glucan cellobiohydrolase (C₁), 1,4-β-d-glucan 4-glucanohydrolase (C_x), β-glucosidase, β-galactosidase, polygalacturonase, proteinase, xylanase, amylase, esterase and ‘polyphenoloxidase’. Isolation of cellulolytic enzymes was performed starting with adsorption chromatography on Avicel SF, leading to separation of more than 90% of non-cellulolytic enzymes and 96% of β-glucosidase activity (= fraction A). In fraction A, 30% of the C_x activity was determined whereas, in a separated fraction, B, the remaining C_x and the total C₁ activity was established. Further fractionation of B using ion-exchange and gel chromatography resulted in the separation of three purified enzyme fractions, PI to PIII, with endo C_x activities. Additionally, C₁ activity was found in PIII. PI-PIII were characterized by means of their pH optima, isoelectric points and molecular weights.