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Demonstration of In Situ Oxidative Degradation of Lignin Side Chains by Two White‐rot Fungi Using Analytical Pyrolysis of Methylated Wheat Straw
Author(s) -
Camarero Susana,
Galletti Guido C.,
Martínez Angel T.
Publication year - 1997
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/(sici)1097-0231(19970228)11:4<331::aid-rcm844>3.0.co;2-h
Subject(s) - lignin , chemistry , biodegradation , pyrolysis , organic chemistry , straw , pleurotus eryngii , vanillic acid , laccase , radical , syringic acid , degradation (telecommunications) , raw material , antioxidant , enzyme , inorganic chemistry , telecommunications , gallic acid , computer science
Lignin biodegradation is an oxidative process involving the action of fungal enzymes and the subsequent chemical reactions of aromatic radicals formed. Aromatic acid release has been reported during biodegradation of lignocellulosic materials, suggesting oxidative degradation of side chains in lignin units. In the present study, wheat lignin degradation by two basidiomycetes was investigated by pyrolysis coupled to GC/MS after sample permethylation. In this way, analysis of phenolic and etherified lignin units, yielding C4‐OMe and C4‐OH compounds respectively, was performed. The amount of etherified residues of carboxy‐free vanillic and syringic acids was found to be very low in sound straw. However, the molar abundances of these acid residues increased strongly during fungal degradation of lignin. For example, each of them attained 8% of total lignin‐derived compounds recovered after pyrolysis of straw treated with Pleurotus eryngii (after 50% lignin degradation). These findings support C α ‐C β cleavage as one of the most frequent reactions during lignin biodegradation, and constitute evidence for in situ cleavage of lignin side chains during fungal attack to this macromolecule. © 1997 John Wiley & Sons, Ltd.