USE OF ACID-TOLERANT XYLANASE FOR BLEACHING OF KRAFT PULPS

A xylanase from Aspergillus kawachii, active at pH 2.0-2.5, was found to be suitable for improvement of bleachability. Due to the low workin g pH of the xylanase, the metal cations were also removed and thus the metal removal stage using chelating agents could be omitted. The use of acid-tolerant xylanase is especially beneficial prior to ozone or c hlorine dioxide bleaching stages due to the minimization of pH adjustm ent steps during bleaching.