Hydrolysis of filter paper by cellulase preparations from Trichoderma viride and Pestalotiopsis westerdijkii adjusted to equal activities on carboxymethyl cellulose. Culture filtrates diluted to 19 Cx units per ml. 0.5 ml enzyme + 1 ml pH 4.8 buffer + 50 mg paper. Incubated at 50°C. White triangle, Tv QM9123 culture filtrate; white circle, Tv QM9414 culture filtrate; black triangle, Pw QM381 culture filtrate.