Laccase catalyzed covalent coupling of fluorophenols increases lignocellulose surface hydrophobicity

• Published in: Bioresource technology 2010-04, Vol.101 (8), p.2793-2799
• Main Authors: Kudanga, Tukayi, Prasetyo, Endry Nugroho, Widsten, Petri, Kandelbauer, Andreas, Jury, Sandra, Heathcote, Carol, Sipilä, Jussi, Weber, Hansjoerg, Nyanhongo, Gibson S., Guebitz, Georg M.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; chemical bonding; Chromatography, High Pressure Liquid; Coupling; enzymatic hydrolysis; ethers; Fagus - chemistry; Fagus sylvatica; fluorophenol; Fluoropolymers; Functionalization; Fundamental and applied biological sciences. Psychology; Guaifenesin - analogs & derivatives; Guaifenesin - metabolism; high performance liquid chromatography; Hydrophobic and Hydrophilic Interactions; hydrophobicity; Laccase; Laccase - metabolism; lignin; Lignin - metabolism; lignocellulose; liquid chromatography; Magnetic Resonance Spectroscopy; Mass Spectrometry; Molecular Structure; nuclear magnetic resonance spectroscopy; oxidation; phenols; Phenols - metabolism; Photoelectron Spectroscopy; Surface Properties; Wood - metabolism; Wood hydrophobicity; wood properties
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2009.12.002

This work presents for the first time the mechanistic evidence of a laccase-catalyzed method of covalently grafting hydrophobicity enhancing fluorophenols onto Fagus sylvatica veneers. Coupling of fluorophenols onto complex lignin model compounds guaiacylglycerol β-guaiacyl ether and syringylglycerol β-guaiacyl ether was demonstrated by LC–MS and NMR. Laccase-mediated coupling increased binding of 4-[4-(trifluoromethyl)phenoxy]phenol (4,4-F3MPP) and 4-(trifluoromethoxy)phenol (4-F3MP) to veneers by 77.1% and 39.2%, respectively. XPS studies showed that laccase-catalyzed grafting of fluorophenols resulted in a fluorine content of 6.39% for 4,4-F3MPP, 3.01% for 4-F3MP and 0.26% for 4-fluoro-2-methylphenol (4,2-FMP). Grafting of the fluorophenols 4,2-FMP, 4-F3MP and 4,4-F3MPP led to a 9.6%, 28.6% and 65.5% increase in hydrophobicity, respectively, when compared to treatments with the respective fluorophenols in the absence of laccase, in good agreement with XPS data.