IMPROVEMENT OF THE QUALITY OF WASTE PAPER BY TREATMENT WITH ENZYMES

The increasing usage of waste paper in the furnish, particularly for g raphic papers, will also lead to increasing demands on the quality of waste papers. Treatment with cellulases and hemicellulases has been su ggested as one possible means of improving waste paper quality. On the one hand the drainage of the stock is thus to be improved, on the oth er hand enzymes may also be used as flotation aids. In this article so me basic aspects of enzymatic treatment of waste paper will be discuss ed in detail. The effects of filtrates of cultures and of pure enzymes on the fibre length distribution and on the dewatering properties are considered. It appears, that the positive effect, which could be achi eved by cellulase treatment, could not be realized without a negative effect on strength properties. Under present conditions the use of enz ymes in waste paper preparation does not appear to be a sensible propo sition.