Use of enzymes to improve the refining of a bleached Eucalyptus globulus kraft pulp

The effect of cellulases and beta-glucanases was evaluated for energy savings in the papermaking refining process. Two commercial enzyme preparations, Celluclast 1.5 L® (cellulases mixture) and Viscozyme L® (carbohydrases mixture) were used to improve the refining process of a bleached Eucalyptus globulus kraft pulp, using different enzyme dosages and different reaction times. This treatment improved pulp drainability (expressed as Schopper–Riegler degree) by up to 80% at the same level of refining energy (1500 PFI revolutions). These results were more significant for cellulases treatment. Pulp degradation was evaluated by the pulp viscosity determination, which was in agreement with the fibre length determination that showed a slight reduction with the enzymatic treatment. The strength properties of the pulp were not affected by enzyme treatment; in fact an increase was observed in paper internal bonding.