Coupling of manganese peroxidase-mediated lipid peroxidation with destruction of nonphenolic lignin model compounds and 14C-labeled lignins.
Linoleic acid, the predominant unsaturated fatty acid (UFA) in the lipids of wood-rotting fungi, was oxidized by manganese peroxidase (MnP) from the white-rot fungus Phlebia radiata through a peroxidation mechanism. The peroxidation was markedly stimulated by hydrogen peroxide. UFAs that are substrates for lipid peroxidation and surfactants that emulsify water-insoluble components were essential for the MnP-catalyzed destruction of a nonphenolic beta-O-4-linked lignin model compound (LMC). Moreover, both components stimulated the MnP-catalyzed mineralization of 14C-labeled synthetic lignin and 14C-labeled wheat straw. A high level of destruction was obtained in reaction systems with Tween 80 acting both as surfactant and source of UFAs. The presence of the linoleic acid in reaction systems with MnP and Tween 80 additionally enhanced rate and level of LMC destruction and lignin mineralization. The results indicate that lipid peroxidation may play an important role in lignin biodegradation by wood-rotting basidiomycetes and support the hypothesis of coupling between the processes.
Kapich
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Institute of Microbiology, Belarussian Academy of Sciences, Minsk, Belarus. ankapich@facstaff.wisc.edu
Hofrichter
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Vares
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Hatakka
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D001487:Basidiomycota / Q000201:enzymology; D001673:Biodegradation, Environmental; D002250:Carbon Radioisotopes / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005609:Free Radicals / Q000737:chemistry; D005656:Fungal Proteins / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007700:Kinetics; D008031:Lignin / Q000378:metabolism*; D019787:Linoleic Acid / Q000378:metabolism; D008041:Linoleic Acids / Q000378:metabolism; D015227:Lipid Peroxidation; D008054:Lipid Peroxides / Q000378:metabolism; D010101:Oxygen Consumption; D010544:Peroxidases / Q000378:metabolism*; D013501:Surface-Active Agents / Q000494:pharmacology; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis
D002250:Carbon Radioisotopes; D005231:Fatty Acids, Unsaturated; D005609:Free Radicals; D005656:Fungal Proteins; D008041:Linoleic Acids; D008054:Lipid Peroxides; D013501:Surface-Active Agents; D017392:Thiobarbituric Acid Reactive Substances; C008285:linoleic acid hydroperoxide; D008031:Lignin; D019787:Linoleic Acid; D006861:Hydrogen Peroxide; D010544:Peroxidases; C051129:manganese peroxidase