Production, partial characterization and use of fungal cellulase-free xylanases in pulp bleaching

L. P. Christov, G. Szakacs, H. Balakrishnan

Research output: Contribution to journalArticle

77 Citations (Scopus)


Seven fungal strains were screened for their ability to produce cellulase-free xylanases that could be used in pretreatment of sulphite pulp prior to bleaching. The potential xylanase producers were subjected to shake flask fermentations using four different carbon sources: wheat bran, corn cobs, oat spelts xylan and bleach plant effluent. When grown on corn cobs, Aspergillus foetidus (ATCC 14916) produced significant levels of xylanase (547.4 U/ml), accompanied however by 6.6 U/ml of cellulase activity. Two other strains, Aspergillus oryzae (NRRL 1808) and Gliocladium viride (CBS 658.70), produced high yields of cellulase-free xylanase on oat spelts xylan. The crude enzymes of these two isolates were characterized with respect to pH and temperature optima and stability in order to standardize the optimum conditions for their use on pulp. Although the two xylanases differed in their abilities to remove reducing sugars from pulp, their biobleaching abilities, when assessed in hydrogen peroxide delignification of pulp, were very similar: both of them increased brightness by 1.4 points and removed 7% of hemicellulose from pulp.

Original languageEnglish
Pages (from-to)511-517
Number of pages7
JournalProcess Biochemistry
Issue number5
Publication statusPublished - Jul 1 1999



  • Aspergillus oryzae
  • Biobleaching
  • Bleach plant effluent
  • Cellulase-free xylanases
  • Gliocladium viride
  • Sulphite pulp

ASJC Scopus subject areas

  • Bioengineering
  • Biochemistry
  • Applied Microbiology and Biotechnology

Cite this