METHOD OF DEINKING WASTE PAPER BY USING CELLULASE WITHOUT LOWERING PAPER STRENGTH AND METHOD OF EVALUATING THE SAME

摘要

A deinking method using a cellulase which enables the load upon the environment to be reduced; and an evaluation method whereby a cellulase effective in deinking and the effective addition level of the cellulase can be appropriately determined. By proposing pulp-swelling activity (PSA) that elevates the water-retention value of pulp after pulp is reacted with cellulase, it becomes possible to select an enzyme that is effective in cellulase-deinking treatment without lowering the paper strength and to determine the effective enzyme dosage. Namely, a method of deinking waste paper is provided wherein the selection of an effective cellulase and the optimization of the enzyme dosage with the use of PSA as an indication make it possible to minimize the cellulase addition level and lessen the amount of the deinking agent.