TRICHODERMA-REESEI CELLULASES IN THE BLEACHING OF KRAFT PULP

In this work the effects of individual purified cellulases of Trichode rma reesei were studied in the enzyme-aided bleaching of kraft pulps. The cellobiohydrolases I and II, when used alone, had no positive effe ct on the bleachability of kraft pulps. The endoglucanase I (EG I), ho wever, acted on pulp similarly to xylanases and with an enzyme dosage of 0.1 mg/g a clear increase in pulp brightness could be observed. Due to the unspecificity of this enzyme, the viscosity of the pulp was si multaneously decreased. Of the cellulases, EG II was clearly most detr imental in reducing the pulp viscosity. Hence, the action of purified cellulases of T. reesei on pulp as a substrate differs profoundly, and all cellulases are not detrimental to the pulp properties.