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Structural Characterization of Lignin during Pinus taeda Wood Treatment with Ceriporiopsis subvermispora

2004; American Society for Microbiology; Volume: 70; Issue: 7 Linguagem: Inglês

10.1128/aem.70.7.4073-4078.2004

1098-5336

Anderson Guerra, Regis Teixeira Mendonça, André Ferraz, Fachuang Lu, John Ralph,

Biochemical and biochemical processes

ABSTRACT Pinus taeda wood chips were biotreated with Ceriporiopsis subvermispora under solid-state fermentation for periods varying from 15 to 90 days. Milled wood lignins extracted from sound and biotreated wood samples were characterized by wet-chemical and spectroscopic techniques. Treatment of the lignins by derivatization followed by reductive cleavage (DFRC) made it possible to detect DFRC monomers and dimers that are diagnostic of the occurrence of arylglycerol-β- O -aryl and β-β, β-5, β-1, and 4- O -5 units in the lignin structure. Quantification of these DFRC products indicated that β- O -aryl cleavage was a significant route for lignin biodegradation but that β-β, β-5, β-1, and 4- O -5 linkages were more resistant to the biological attack. The amount of aromatic hydroxyls did not increase with the split of β- O -4 linkages, suggesting that the β- O -4 cleavage products remain as quinone-type structures as detected by UV and visible spectroscopy. Nuclear magnetic resonance techniques also indicated the formation of new substructures containing nonoxygenated, saturated aliphatic carbons (CH 2 and CH 3 ) in the side chains of lignins extracted from biotreated wood samples.