Upgrading of Recycled Pulps by Enzymatic Treatment, 1994 Recycling Symposium Proceedings

G. Stork, H. Pereira, T. M. Wood, E. M.

Dusterhoft, A. Taft, J. Puls

Hydrolytic enzymes were reported to improve the drainage of recycled pulp. However, there is some uncertainty about the nature of the enzymes involved and the underlying mechanism of this phenomenon.

In a joint effort by an European research consortium of microbiologists, biochemists and wood and fiber technologists, waste paper was incubated with culture filtrates and with isolated cellulases and hemicellulases. It was found that the action of endoglucanases was necessary for an improvement in the drainage of waste paper. The effect did not appear to be due to a selective hydrolysis of the fines fraction, but was a consequence of the hydrolysis of amorphous cellulose on the surface of the fibers. Depending on the origin and history of primary and secondary fibers the endoglucanase treatment decreased the strength properties to differing degrees. It is demonstrated that endoglucanase treatment is best suited for the treatment of waste paper consisting of mechanical pulp, but not for those papers containing considerable amounts of chemical pulp fibers.