TCF mill trial on softwood pulp with Korsäs thermostable and alkaline stable xylanase T6

Kerstin Rodell Lundgren*, Leif Bergkvist, Stefan Högman, Håkan Jöves, Göran Eriksson, Tamas Bartfai, Joop van der Laan, Eugene Rosenberg, Yuval Shoham

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Use of hemicellulases, including xylanases, for delignification in the paper industry has been slowed down by the lack of large-scale availability of enzymes which are active at a high pH (above 8) and a high temperature (above 60°C), conditions prevailing in many bleaching processes. During the past years, acidic or neutral hemicellulases, working at temperatures below 60°C, were used in most mill experiments. The Korsäs T6 xylanase from Bacillus stearothermophilus, which is active at a pH above 9.0 and at a temperature above 65°C, was produced on a large scale in collaboration with Gist-brocades and was employed on a full scale mill trial to produce a Total Chlorine chemical-Free (TCF) pulp from softwood. The bleaching sequence used was (OO)BQQPP. where O stands for oxygen delignification. B for the enzymatic treatment, Q for the chelating agent step and P for the hydrogen peroxide step. The enzyme bleaching step was performed during a period of 4 h at 63 ± 1°C and pH 8.7 ± 0.1. The results of the mill trial show that the TCF pulp produced had a brightness of 78% ISO and, at the same time, it preserved the same strength properties as chlorine dioxide-bleached pulp. The saving of hydrogen peroxide was 20%. The results on brightness, strength and chemical saving of this first full scale trial with T6 xylanase indicate that, after optimization, a TCF bleaching sequence including an enzymatic step with a xylanase working at a high pH and a high temperature, such as T6 xylanase, can be used to produce a high-strength bleached pulp. The advantages of a high pH and a high temperature enzymatic bleaching step are discussed.

Original languageEnglish
Pages (from-to)365-368
Number of pages4
JournalFEMS Microbiology Reviews
Issue number2-3
StatePublished - Mar 1994


  • Bleaching
  • Hemicellulase
  • Temperature optimum
  • Xylanase
  • pH optimum


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