title: Oxidative polymerization of lignins by laccase in water-acetone mixture.
abstract: The enzymatic oxidative polymerization of five technical lignins with different molecular properties, i.e. Soda Grass/Wheat straw Lignin, Organosolv Hardwood Lignin, Soda Wheat straw Lignin, Alkali pretreated Wheat straw Lignin, and Kraft Softwood was studied. All lignins were previously fractionated by acetone/water 50:50 (v/v) and the laccase-catalyzed polymerization of the low molecular weight fractions (Mw < 4000 g/mol) was carried out in the same solvent system. Reactivity of lignin substrates in laccase-catalyzed reactions was determined by monitoring the oxygen consumption. The oxidation reactions in 50% acetone in water mixture proceed with high rate for all tested lignins. Polymerization products were analyzed by size exclusion chromatography, FT-IR, and (31)P-NMR and evidence of important lignin modifications after incubation with laccase. Lignin polymers with higher molecular weight (Mw up to 17500 g/mol) were obtained. The obtained polymers have potential for applications in bioplastics, adhesives and as polymeric dispersants.
authors.affiliation: "Politehnica" University of Timişoara, Faculty of Industrial Chemistry and Environmental Engineering, Timişoara, Romania; National Institute of Research-Development for Electrochemistry and Condensed Matter, Timişoara, Romania.
authors.forename: Ionița Firuța
authors.initials: IF
authors.lastname: Fiţigău
authors.affiliation: "Politehnica" University of Timişoara, Faculty of Industrial Chemistry and Environmental Engineering, Timişoara, Romania.
authors.forename: Francisc
authors.initials: F
authors.lastname: Peter
authors.affiliation: Wageningen UR Food & Biobased Research, Wageningen, Netherlands; University "Aurel Vlaicu" of Arad, Department of Life Sciences, Arad, Romania.
authors.forename: Carmen Gabriela
authors.initials: CG
authors.lastname: Boeriu
mesh_terms: D000096:Acetone / Q000737:chemistry; D002850:Chromatography, Gel; D042845:Laccase / Q000737:chemistry* / Q000378:metabolism; D008031:Lignin / Q000737:chemistry* / Q000378:metabolism; D010084:Oxidation-Reduction; D058105:Polymerization; D012997:Solvents / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D014908:Triticum / Q000737:chemistry* / Q000378:metabolism; D014867:Water / Q000737:chemistry
chemical_list: D012997:Solvents; D014867:Water; D000096:Acetone; D008031:Lignin; D042845:Laccase