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Applied Microbiology and Biotechnology

, Volume 48, Issue 4, pp 459–464 | Cite as

Identification and quantification of radical reaction intermediates by electron spin resonance spectrometry of laccase-catalyzed oxidation of wood fibers from beech (Fagus sylvatica)

  • C. Felby
  • B. R. Nielsen
  • P. O. Olesen
  • L. H. Skibsted
ORIGINAL PAPER

Abstract

During laccase-catalyzed oxidation of beech wood fibers in an aqueous suspension, phenoxy radicals were detected in steady-state concentrations by electron-spin resonance (ESR) spectrometry of the suspension liquid, suggesting that colloidal lignin functions as a mediator between laccase and the fiber lignin matrix. Phenoxy radicals were observed directly, whereas ESR spin-trapping techniques gave no evidence for reduced oxygen species, such as the superoxide or hydroxyl radical. A reaction mechanism involving parallel direct oxidation of the lignin on fiber surfaces and a phenol/phenoxy cyclic mediator process in the suspension liquid could accordingly describe laccase-catalyzed oxidation of beech wood fibers. Cytochrome c assays for detection of superoxide in systems involving lignin oxidized by oxidoreductases should be used with caution, as cytochrome c may be reduced by species other than superoxide.

Keywords

Lignin Superoxide Electron Spin Resonance Fiber Surface Oxidoreductase 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • C. Felby
    • 1
  • B. R. Nielsen
    • 2
  • P. O. Olesen
    • 1
  • L. H. Skibsted
    • 2
  1. 1.Plant Fibre Laboratory, Royal Veterinary and Agricultural University, Agrovej 10, DK-2630 Taastrup, DenmarkDK
  2. 2.Department of Dairy and Food Science, Royal Veterinary and Agricultural University, Rolighedsvej 30, DK-1958 Frederiksberg C, DenmarkDK

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