2011年
Alkoxyl- and carbon-centered radicals as primary agents for degrading non-phenolic lignin-substructure model compounds
ORGANIC & BIOMOLECULAR CHEMISTRY
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- 巻
- 9
- 号
- 7
- 開始ページ
- 2481
- 終了ページ
- 2491
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1039/c0ob00797h
- 出版者・発行元
- ROYAL SOC CHEMISTRY
Lignin degradation by white-rot fungi proceeds via free radical reaction catalyzed by oxidative enzymes and metabolites. Basidiomycetes called selective white-rot fungi degrade both phenolic and non-phenolic lignin substructures without penetration of extracellular enzymes into the cell wall. Extracellular lipid peroxidation has been proposed as a possible ligninolytic mechanism, and radical species degrading the recalcitrant non-phenolic lignin substructures have been discussed. Reactions between the non-phenolic lignin model compounds and radicals produced from azo compounds in air have previously been analysed, and peroxyl radical (PR) is postulated to be responsible for lignin degradation (Kapich et al., FEBS Lett., 1999, 461, 115-119). However, because the thermolysis of azo compounds in air generates both a carbon-centred radical (CR) and a peroxyl radical (PR), we re-examined the reactivity of the three radicals alkoxyl radical (AR), CR and PR towards non-phenolic monomeric and dimeric lignin model compounds. The dimeric lignin model compound is degraded by CR produced by reaction of 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH), which under N-2 atmosphere cleaves the alpha-beta bond in 1-(4-ethoxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol to yield 4-ethoxy-3-methoxybenzaldehyde. However, it is not degraded by the PR produced by reaction of Ce4+/tert-BuOOH. In addition, it is degraded by AR produced by reaction of Ti3+/tert-BuOOH. PR and AR are generated in the presence and absence of veratryl alcohol, respectively. Rapid-flow ESR analysis of the radical species demonstrates that AR but not PR reacts with the lignin model compound. Thus, AR and CR are primary agents for the degradation of non-phenolic lignin substructures.
- リンク情報
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- DOI
- https://doi.org/10.1039/c0ob00797h
- J-GLOBAL
- https://jglobal.jst.go.jp/detail?JGLOBAL_ID=201102277849633807
- PubMed
- https://www.ncbi.nlm.nih.gov/pubmed/21327224
- Web of Science
- https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000288456700054&DestApp=WOS_CPL
- ID情報
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- DOI : 10.1039/c0ob00797h
- ISSN : 1477-0520
- eISSN : 1477-0539
- J-Global ID : 201102277849633807
- PubMed ID : 21327224
- Web of Science ID : WOS:000288456700054