Oxidation of lignans and lignin model compounds by laccase in aqueous solvent systems

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Maija-Liisa Mattinen, Pekka Maijala, Paula Nousiainen, Annika Smeds, Jussi Kontro, Jussi Sipilä, Tarja Tamminen, Stefan Willför, Liisa Viikari
Publisher: ELSEVIER SCIENCE BV
Publication year: 2011
Journal: Journal of Molecular Catalysis B: Enzymatic
Journal acronym: J MOL CATAL B-ENZYM
Volume number: 72
Issue number: 3-4
Start page: 122
End page: 129
Number of pages: 8
ISSN: 1381-1177
eISSN: 1873-3158


Abstract

The stability and activity of the low redox potential Melanocarpus albomyces laccase (MaL) in various aqueous organic (acetone, ethanol, propylene glycol, diethylene glycol monomethyl ether) solvent systems was studied spectrophotometrically using 2,6-dimethoxyphenol (2,6-DMP) as substrate. In addition, reactivity of the enzyme with two lignans; matairesinol (MR) and 7-hydroxymatairesinol (HMR), was examined by oxygen consumption measurements in the most potential aqueous organic solvent systems. Polymerization of the lignans by MaL was verified by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and size exclusion chromatography (SEC). Polymerization of the higher molecular weight lignin model compound, dehydrogenation polymers (DHPs), was studied by SEC. The solubilities of industrial softwood and hardwood kraft lignins were evaluated as parameters for investigation of enzymatic modification in aqueous organic solvent systems. The functioning of MaL in different aqueous organic media was excellent. Propylene glycol and diethylene glycol monomethyl ether were better solvents than ethanol or acetone in enzymatic oxidations. Even though they were the best solvents for enzyme oxidation, ethanol and propylene glycol were selected for further tests because of their different physicochemical properties. The results obtained in this study for the use of laccase-catalysed reactions in organic solvents to improve the efficiency of lignin oxidation may be exploited in several applications and areas in which the solubility of the reactants or products is a limiting factor.


Keywords

Dehydrogenation polymers, Laccase, Lignin, Melanocarpus albomyces, Reactivity, Solvent

Last updated on 2019-22-09 at 02:41