Effects of enzymatic treatment on cellulosic fibres from recycled paper. Analysis of the experimental design

Abstract

An enzymatic preparation consisting of cellulases and hemicellulases significantly affected the drainability and strength properties of an unbleached softwood Kraft pulp repulped in laboratory. The independent variables, treatment time and enzyme dose, were analysed using a central composite design for both the whole pulp and its fibrous fractions. Statistical analysis showed significant improvements in drainability. The effects of enzymatic treatments on strength properties were: increase in tensile index and apparent density and decrease in tear index and light scattering coefficients. Changes in fibre surfaces (initial and with enzyme treatment) could be observed by Simons´ differential stain.