A novel diffusible system capable of decomposing lignin model compounds with copper, coordinators and peroxides has been proposed. When pyridine was used as a copper coordinator, two synthetic dyes, Poly-R and RBBR were intensively decolorized with Cu(II) and H2O2 in aqueous solutions at room temperature. Although reactions with Cu(II) and H2O2 produce a strong oxidant, hydroxyl radical, via a Fenton pathway, the coordinated copper system presented here was much more effective than the simple Fenton reaction for decolorizing the polymeric dyes. In contrast to the dye decolorization, the Cu(II)/pyridine/H2O2 system was not effective for depolymerizing 14 C-labeled synthetic lignin. However, phenolic and nonphenolic lignins were extensively decomposed by Cu(II) and pyridine in the presence of lipid hydroperoxide model compounds in aqueous solution at room temperature. Since pyridine is produced by ligninolytic fungi and the pyridine nucleus is an essential component of fungal metabolites, we herein propose that the copper/coordination compound/peroxide could be involved in decomposition or modification of lignin during wood rotting.

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