T. Shimokawa, M. Nakamura, N. Hayashi, M. Ishihara
Production of 2,5-dimethoxyhydroquinone by the brown-rot fungus Serpula lacrymans to drive extracellular Fenton reaction
The brown-rot fungus Serpula lacrymans MAFF 420003
was grown in a liquid culture medium containing 0.5%
carboxymethyl cellulose (CMC) and 1% glucose as carbon
sources. Although little extracellular cellulase was
secreted, the fungus produced an oxidized quinone-type
chelator, 2,5-dimethoxy-1,4-benzoquinone (2,5-DMBQ).
The concentration of 2,5-DMBQ in the medium reached
a maximum of 90 ?mm after a month of cultivation. S.
lacrymans could reduce 2,5-DMBQ to 2,5-dimethoxyhydroquinone
(2,5-DMHQ), thus a biological Fenton reaction
was adopted by the fungus. The changes in the
molecular weight distribution of CMC and arabinogalactan
were analyzed after the addition of 2,5-DMHQ and
Fe3+. CMC was apparently depolymerized by the reaction,
but the same reaction conditions showed no significant
effect on arabinogalactan. These differences
suggest the specificities of the biological Fenton reaction
via 2,5-DMBQ toward soluble polysaccharides. In addition,
the crystallinity index of ?-cellulose did not
decrease as a result of the reaction with 2,5-DMHQ and
Fe3+. These results provide indirect evidence that S. lacrymans
employs a biological Fenton reaction mediated
by a quinone-type chelator, and preferentially degrades
amorphous regions of cellulose rather than crystalline
regions in the non-enzymatic cellulose degradation.
Holzforschung, Walter de Gruyter
Print ISSN: 0018-3830
Volume: 58, 05/2004
Pages: 305 - 310
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