Oxidative cleavage of non-phenolic β-O-4 lignin model dimmers by an extracellular aromatic peroxygenase

Matthias Kinne*, Marzena Poraj-Kobielska, René Ullrich, Paula Nousiainen, Jussi Sipilä, Katrin Scheibner, Kenneth E. Hammel, Martin Hofrichter

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

26 Citations (Scopus)

Abstract

The extracellular aromatic peroxygenase of the agaric fungus Agrocybe aegerita catalyzed the H 2O 2-dependent cleavage of non-phenolic arylglycerol-β-aryl ethers (β-O-4 ethers). For instance 1-(3,4-dimethoxyphenyl)-2-(2-methoxy-phenoxy)propane- 1,3-diol, a recalcitrant dimeric lignin model compound that represents the major non-phenolic substructure in lignin, was selectively O-demethylated at the para-methoxy group to give formaldehyde and 1-(4-hydroxy-3-methoxyphenyl)- 2-(2-methoxyphenoxy) propane-1,3-diol. The phenol moiety of the latter compound was then enzymatically oxidized into phenoxy radicals and a quinoid cation, which initiated the autocatalytic cleavage of the dimer and the formation of monomers such as 2-methoxy-1,4-benzoquinone and phenoxyl-substituted propionic acid. The introduction of 18O from H 2 18O 2 and H 2 18O at different positions into the products provided information about the routes of ether cleavage. Studies with a 14C-labeled lignin model dimer showed that more than 70% of the intermediates formed were further coupled to form polymers with molecular masses above 10 kDa. The results indicate that fungal aromatic peroxygenases may be involved in the bioconversion of methoxylated plant ingredients originating from lignin or other sources.

Original languageEnglish
Pages (from-to)673-679
Number of pages7
JournalHolzforschung
Volume65
Issue number5
DOIs
Publication statusPublished - Aug 2011
MoE publication typeA1 Journal article-refereed

Keywords

  • Agrocybe aegerita
  • Hydroxylation
  • Lignin model compound
  • O-dealkylation
  • Peroxidase
  • Peroxygenase

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