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In vitro and in vivo oxidation of diastereomers of lignin models of arylgylcerol b-aryl ether type and heterologous expression of laccase
Karlstad University, Faculty of Technology and Science.
2008 (English)Doctoral thesis, comprehensive summary (Other academic)Alternative title
(English)
Abstract [en]

Enzymic and non-enzymic oxidation of lignin models of the arylglycerol β-aryl ether type was investigated in experiments aimed at providing a better understanding of the initial phase of biological lignin degradation. Product profiles and diasteromer selectivity were determined to gain knowledge of the properties of the oxidants and pave the way for evaluation of the presence of the oxidants in ligninolytic fungal cultures.

Diastereomers of the non-phenolic lignin model 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol (1) were oxidized in vitro with lignin peroxidase (LP), laccase-mediator systems, Fenton's reagent, cerium(IV) ammonium nitrate (CAN) and lead(IV) tetraacetate. The product profiles were found to be distinctive for the different oxidants, except for LP and CAN, which generated the same products in similar proportions. The reactions resulted in preferential degradation of the threo isomer, except for the Fenton's reagent reaction, which showed no stereo-preference, and the laccase reaction mediated by ABTS, which preferentially degraded the erythro isomer. Cultures of the white-rot fungi Trametes versicolor and Phanerochaete chrysosporium preferentially degraded the threo isomer of 1. This is not in agreement with the action of Fenton's reagent, since this oxidant does not exhibit any stereo-preference.

Laccase from T. versicolor was expressed in Pichia pastoris and Aspergillus niger. Production of catalytically active T. versicolor laccase was achieved in both P. pastoris and A. niger using glyceraldehyde-3-phosphate dehydrogenase promoters. The level of laccase activity obtained with P. pastoris was significantly lower than that obtained with A. niger, but speed and convenience make the P. pastoris system attractive for screening purposes. A. niger produced high yields of heterologous laccase with properties similar to those of the native enzyme. A method was devised to purify laccase from cultures of A. niger. The method gave a 250-fold purification and a yield of >50%.

Place, publisher, year, edition, pages
2008.
Series
Karlstad University Studies, ISSN 1403-8099 ; 2008:9
National Category
Biochemistry and Molecular Biology
Research subject
Chemistry
Identifiers
URN: urn:nbn:se:kau:diva-1536ISBN: 978-91-7063-167-2 (print)OAI: oai:DiVA.org:kau-1536DiVA: diva2:5442
Public defence
2008-04-04, Ericssonsalen, 9C 204, Karlstads Universitet, Karlstad, 13:15 (English)
Opponent
Supervisors
Available from: 2008-03-17 Created: 2008-03-17 Last updated: 2009-04-28
List of papers
1. Product profiles in enzymic and non-enzymic oxidations of the lignin model compound erythro-1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol
Open this publication in new window or tab >>Product profiles in enzymic and non-enzymic oxidations of the lignin model compound erythro-1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol
Show others...
2005 (English)In: Journal of Molecular Catalysis B: Enzymatic, ISSN 1381-1177, Vol. 35, no 4-6, 100-107 p.Article in journal (Refereed) Published
Identifiers
urn:nbn:se:kau:diva-1996 (URN)10.1016/j.molcatb.2005.06.003 (DOI)
Available from: 2008-03-17 Created: 2008-03-17 Last updated: 2010-09-20Bibliographically approved
2. Differences in stereo-preference in the oxidative degradation of diastereomers of the lignin model compound 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1-1,3-propanediol with enzymic and non-enzymic oxidants
Open this publication in new window or tab >>Differences in stereo-preference in the oxidative degradation of diastereomers of the lignin model compound 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1-1,3-propanediol with enzymic and non-enzymic oxidants
2007 (English)In: Journal of Molecular Catalysis B: Enzymatic, ISSN 1381-1177, Vol. 45, no 1-2, 21-26 p.Article in journal (Refereed) Published
Identifiers
urn:nbn:se:kau:diva-1997 (URN)10.1016/j.molcatb.2006.11.001 (DOI)
Available from: 2008-03-17 Created: 2008-03-17 Last updated: 2010-09-20Bibliographically approved
3. Diastereomer selectivity in the degradation of a lignin model compound of the arylglycerol β-aryl ether type by white-rot fungi
Open this publication in new window or tab >>Diastereomer selectivity in the degradation of a lignin model compound of the arylglycerol β-aryl ether type by white-rot fungi
2008 (English)In: Enzyme and microbial technology, ISSN 0141-0229, E-ISSN 1879-0909, Vol. 43, no 2, 199-204 p.Article in journal (Refereed) Published
National Category
Chemical Sciences
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-1998 (URN)10.1016/j.enzmictec.2008.03.002 (DOI)
Available from: 2008-03-17 Created: 2008-03-17 Last updated: 2011-11-10Bibliographically approved
4. Oxidation of the erythro and threo forms of the phenolic lignin model compound 1-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol by laccases and model oxidants
Open this publication in new window or tab >>Oxidation of the erythro and threo forms of the phenolic lignin model compound 1-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol by laccases and model oxidants
(English)Manuscript (Other academic)
National Category
Chemical Sciences
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-1999 (URN)
Available from: 2008-03-17 Created: 2008-03-17 Last updated: 2011-11-10Bibliographically approved
5. Heterologous Expression of Trametes versicolor Laccase in Pichia pastoris and Aspergillus niger
Open this publication in new window or tab >>Heterologous Expression of Trametes versicolor Laccase in Pichia pastoris and Aspergillus niger
2006 (English)In: Applied Biochemistry and Biotechnology, ISSN 0273-2289, E-ISSN 1599-0291, Vol. 129, no 1-3, 195-214 p.Article in journal (Refereed) Published
Identifiers
urn:nbn:se:kau:diva-2000 (URN)10.1385/ABAB:129:1:195 (DOI)
Available from: 2008-03-17 Created: 2008-03-17 Last updated: 2010-09-20Bibliographically approved

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