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Laccase catalysed modification of lignin subunits and coupling to p-aminobenzoic acid

Ibrahim, Victor LU ; Volkova, Natalia LU ; Pyo, Sang-Hyun LU ; Mamo, Gashaw LU and Hatti-Kaul, Rajni LU (2013) In Journal of Molecular Catalysis B: Enzymatic 97. p.45-53
Abstract
Laccase catalysed oxidation of syringyl and guaiacyl subunits of lignin and their modification with an aromatic amine, p-aminobenzoic acid (PABA) were investigated. Laccase from Galerina sp. HC1 isolated earlier by us was used as the main catalyst, and Trametes versicolor laccase was used for comparison. Among the syringyl compounds, syringic acid and syringaldehyde were oxidised to 2,6-dimethoxy-1,4-benzoquinone, and in the presence of PABA yielded a cross-coupling imine product. The reaction with methyl syringol resulted in several products whose structures were determined. The possible oxidative coupling pathways were proposed for the formation of the identified products. Oxidation of syringol and the guaiacyl compounds resulted mainly... (More)
Laccase catalysed oxidation of syringyl and guaiacyl subunits of lignin and their modification with an aromatic amine, p-aminobenzoic acid (PABA) were investigated. Laccase from Galerina sp. HC1 isolated earlier by us was used as the main catalyst, and Trametes versicolor laccase was used for comparison. Among the syringyl compounds, syringic acid and syringaldehyde were oxidised to 2,6-dimethoxy-1,4-benzoquinone, and in the presence of PABA yielded a cross-coupling imine product. The reaction with methyl syringol resulted in several products whose structures were determined. The possible oxidative coupling pathways were proposed for the formation of the identified products. Oxidation of syringol and the guaiacyl compounds resulted mainly in homooligomers by free radical mechanism, with a negligible tendency of reaction with the nucleophilic group of PABA. Similar treatment of Eucalyptus Kraft lignin, which is rich in syringyl moieties, showed the presence of identical products obtained with syringic acid and syringaldehyde. (C) 2013 Elsevier B.V. All rights reserved. (Less)
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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Laccase, Syringyl subunits, Guaiacyl subunits, Oxidative coupling, pathways, Structure elucidation
in
Journal of Molecular Catalysis B: Enzymatic
volume
97
pages
45 - 53
publisher
Elsevier
external identifiers
  • wos:000327005000008
  • scopus:84884508373
ISSN
1873-3158
DOI
10.1016/j.molcatb.2013.07.014
language
English
LU publication?
yes
id
089af4de-5f6e-4dd1-a9a6-711b5e706330 (old id 4196491)
date added to LUP
2016-04-01 10:38:55
date last changed
2022-01-26 01:13:14
@article{089af4de-5f6e-4dd1-a9a6-711b5e706330,
  abstract     = {{Laccase catalysed oxidation of syringyl and guaiacyl subunits of lignin and their modification with an aromatic amine, p-aminobenzoic acid (PABA) were investigated. Laccase from Galerina sp. HC1 isolated earlier by us was used as the main catalyst, and Trametes versicolor laccase was used for comparison. Among the syringyl compounds, syringic acid and syringaldehyde were oxidised to 2,6-dimethoxy-1,4-benzoquinone, and in the presence of PABA yielded a cross-coupling imine product. The reaction with methyl syringol resulted in several products whose structures were determined. The possible oxidative coupling pathways were proposed for the formation of the identified products. Oxidation of syringol and the guaiacyl compounds resulted mainly in homooligomers by free radical mechanism, with a negligible tendency of reaction with the nucleophilic group of PABA. Similar treatment of Eucalyptus Kraft lignin, which is rich in syringyl moieties, showed the presence of identical products obtained with syringic acid and syringaldehyde. (C) 2013 Elsevier B.V. All rights reserved.}},
  author       = {{Ibrahim, Victor and Volkova, Natalia and Pyo, Sang-Hyun and Mamo, Gashaw and Hatti-Kaul, Rajni}},
  issn         = {{1873-3158}},
  keywords     = {{Laccase; Syringyl subunits; Guaiacyl subunits; Oxidative coupling; pathways; Structure elucidation}},
  language     = {{eng}},
  pages        = {{45--53}},
  publisher    = {{Elsevier}},
  series       = {{Journal of Molecular Catalysis B: Enzymatic}},
  title        = {{Laccase catalysed modification of lignin subunits and coupling to p-aminobenzoic acid}},
  url          = {{http://dx.doi.org/10.1016/j.molcatb.2013.07.014}},
  doi          = {{10.1016/j.molcatb.2013.07.014}},
  volume       = {{97}},
  year         = {{2013}},
}