title: Degradation of benzyl ether bonds of lignin by ruminal microbes.
abstract: We examined microbial activity in the rumen to cleave benzyl ether bonds of lignin model compounds that fluoresced when the bonds were cleaved. 4-Methylumbelliferone veratryl ether dimer was degraded completely within 8 h even in the presence of fungicidal antibiotics, but no significant degradation occurred with bactericidal antibiotics. Degradation of a phenolic beta-O-4 trimer incorporating 4-methylumbelliferone by a benzyl ether linkage was stimulated by ruminal microbes, although its corresponding non-phenolic model compound, 1-(4-ethoxy-3-methoxyphenyl)-1-O-(4-methylumbelliferyl)-2-(2-methoxyp henoxy)-3-propanol, was not degraded. A coniferyl dehydrogenation polymer bearing fluorescent beta-O-4 benzyl ether that contains both phenolic and non-phenolic benzyl ether bonds was partially degraded (about 20%) in 48 h. These results suggest that ruminal microbes decompose benzyl ether linkages of lignin polymers under anaerobic conditions.
authors.affiliation: National Institute of Animal Industry, Tsukuba Norindanchi, Ibaraki, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kajikawa
authors.forename: H
authors.initials: H
authors.lastname: Kudo
authors.forename: T
authors.initials: T
authors.lastname: Kondo
authors.forename: K
authors.initials: K
authors.lastname: Jodai
authors.forename: Y
authors.initials: Y
authors.lastname: Honda
authors.forename: M
authors.initials: M
authors.lastname: Kuwahara
authors.forename: T
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002417:Cattle; D062385:Hydroxybenzoates / Q000378:metabolism; D008031:Lignin / Q000737:chemistry / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D012417:Rumen / Q000382:microbiology*; D013997:Time Factors
chemical_list: D062385:Hydroxybenzoates; D008031:Lignin; C017616:phenolic acid