Characterization of the secreted cellulases of Trichoderma reesei wild type and mutants during controlled fermentations

Abstract

The cellulases produced under pH controlled fermentation conditions with 5% Solka Floc and cornsteep liquor as substrates by Trichoderma reesei wild type QM6a and two mutants, Rut-C30 and RL-P37, have been separated by isoelectric focusing in polyacrylamide gels. The total complement of secreted proteins of the two mutants was distinct from the parent. However, the number and isoelectric points of the various enzymes in the cellulase complex were unchanged in the mutants. All secreted proteins stained with Schiff's reagent which indicated they were glycoproteins. One mutant, Rut-C30, exhibited a dramatic shift in the CBH I proteins during the course of the fermentation. RL-P37 showed a two-fold increase in the specific activity of both the total cellulase complex and endoglucanase. In addition a productivity on the order of 100 IU/l/h was achieved. Co-produced with the cellulases were at least two acid proteases with differential activity towards azocoll and azocasein. © 1984 Springer-Verlag.