Method for removing unsaturated uronic acid in chemical pulp for papermaking

Abstract

The present invention provides a method for removing unsaturated uronic acid contained in chemical pulp for papermaking, characterized by adding glucuronidase. According to the preferred embodiment of the present invention, in an ECF or TCF bleaching method using no molecular chlorine, unsaturated uronic acid can be reduced while controlling a bleaching cost, and a brightness reversion property of pulp can be improved.

1 . A method for removing unsaturated uronic acid contained in chemical pulp for papermaking, characterized by adding glucuronidase.  
   
   
       2 . The method of  claim 1 , wherein glucuronidase contains xylosidase or xylanase.  
   
   
       3 . The method of  claim 1 , wherein glucuronidase contains α-glucuronidase.  
   
   
       4 . The method of  claim 2 , wherein glucuronidase contains α-glucuronidase.  
   
   
       5 . The method of  claim 1 , wherein unsaturated uronic acid is hexeneuronic acid.  
   
   
       6 . The method of 1, wherein glucuronidase is produced from basidiomycete or filamentous fungus.  
   
   
       7 . The method of  claim 2 , wherein xylosidase or xylanase is produced from basidiomycete or filamentous fungus.  
   
   
       8 . The method of  claim 6 , wherein the basidiomycete is a  Cholorosplenium  genus.  
   
   
       9 . The method of  claim 6 , wherein the filamentous fungus is an  Aspergillus  genus.  
   
   
       10 . The method of  claim 8 , wherein the  Cholorosplenium  genus is  Cholorosplenium aeruginosum.    
   
   
       11 . The method of  claim 9 , wherein the  Aspergillus  genus is  Aspergillus niger.    
   
   
       12 . The method of  claim 6 , wherein the glucuronidase is produced on a culture medium containing xylan.  
   
   
       13 . The method of  claim 7 , wherein the xylosidase or xylanase is produced on a culture medium containing xylan.  
   
   
       14 . The method of  claim 6 , wherein glucuronidase produced is added to the pulp without refining.  
   
   
       15 . The method of  claim 1 , wherein glucuronidase is added to the pulp after oxygen treatment, during a bleaching treatment step or after bleaching treatment.  
   
   
       16 . The method as described in  claim 15 , wherein the pulp is ECF bleached pulp or TCF bleached pulp.