PRE-BLEACHING TREATMENT METHOD USING ENZYME FOR CHEMICAL PULP

摘要

This invention provides a method of increasing the degree of delignification of chemical pulp without decreasing the viscosity thereof. In this method, unbleached pulp or pulp which has been subjected to oxygen delignification is subjected to a pre-bleaching treatment, in which xylanase having an activity in the range of pH of not more than 4.5 is used, as the pulp is maintained under acidic conditions. This method enables the quantity of use of a medicine of a chlorine compound to be reduced while maintaining such a degree of whiteness of bleached pulp that permits commercial use, whereby the occurrence of an organic chlorine compound which is environmentally harmful can be minimized.