Enzymatically and chemically oxidized lignin nanoparticles for biomaterial applications

Publication date: April 2018 Source:Enzyme and Microbial Technology, Volume 111 Author(s): Maija-Liisa Mattinen, Juan José Valle-Delgado, Timo Leskinen, Tuomas Anttila, Guillaume Riviere, Mika Sipponen, Arja Paananen, Kalle Lintinen, Mauri Kostiainen, Monika Österberg Cross-linked and decolorized lignin nanoparticles (LNPs) were prepared enzymatically and chemically from softwood Kraft lignin. Colloidal lignin particles (CLPs, ca. 200 nm) in a non-malodorous aqueous dispersion could be dried and redispersed in tetrahydrofuran (THF) or in water retaining their stability i.e. spherical shape and size. Two fungal laccases, Trametes hirsuta (ThL) and Melanocarpus albomyces (MaL) were used in the cross-linking reactions. Reactivity of ThL and MaL on Lignoboost™ lignin and LNPs was confirmed by high performance size exclusion chromatography (HPSEC) and oxygen consumption measurements with simultaneous detection of red-brown color due to the formation of quinones. Zeta potential measurements verified oxidation of LNPs via formation of surface-oriented carboxylic acid groups. Dynamic light scattering (DLS) revealed minor changes in the particle size distributions of LNPs after laccase catalyzed radicalization, indicating preferably covalent intraparticular cross-linking over polymerization. Changes in the surface morphology of laccase treated LNPs were imaged by atomic force (AFM) and transmission emission (TEM) microscopy. Furthermore, decolorization of LNPs withou...
Source: Enzyme and Microbial Technology - Category: Biotechnology Source Type: research