Antibacterial effects of knotwood extractives on paper mill bacteria

L. E. Lindberg*, S. M. Willför, B. R. Holmbom

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

76 Citations (Scopus)


Hydrophilic knotwood extracts from 18 wood species were assessed in disc diffusion and liquid culture tests for antibacterial effects against three species of paper mill bacteria. The Pinus sylvestris, P. resinosa, P. contorta, and P. banksiana extracts decreased or inhibited bacterial growth. The susceptibility order was P. sylvestris > P. resinosa > P. contorta > P. banksiana, correlating with the concentrations of pinosylvin and pinosylvin monomethyl ether in these wood species. Also, Pseudotsuga menziesii and Thuja occidentalis extracts had a small inhibitory effect. The Gram-positive Bacillus coagulans was more susceptible to the extracts than the Gram-negative Burkholderia mullivorans and Alcaligenes xylosoxydans. The main components in the Pinus knotwood extracts were pinosylvin monomethyl ether and pinosylvin, suggesting these to be the active components. Therefore, pure pinosylvin, pinosylvin monomethyl ether, and dihydro-pinosylvin monomethyl ether were also tested. All compounds showed antibacterial effects. However, higher concentrations were needed for these pure compounds than for the knotwood extracts. Pinosylvin had stronger antibacterial effects than pinosylvin monomethyl ether. This work shows that knotwood extracts, especially from Pinus species, have a potential for use as natural biocides in papermaking.

Original languageEnglish
Pages (from-to)137-147
Number of pages11
JournalJournal of Industrial Microbiology and Biotechnology
Issue number3
Publication statusPublished - Mar 2004
MoE publication typeA1 Journal article-refereed


  • Alcaligenes xylosoxydans
  • Bacillus coagulans
  • Burkholderia multivorans
  • Hydrophilic extractives
  • Knotwood
  • Natural biocides
  • Pinosylvin
  • Pinosylvin monomethyl ether
  • Stilbenes


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