title: Reactivity of bacterial and fungal laccases with lignin under alkaline conditions.
abstract: The ability of Streptomyces ipomoea laccase to polymerize secoisolariciresinol lignan and technical lignins was assessed. The reactivity of S. ipomoea laccase was also compared to that of low redox fungal laccase from Melanocarpus albomyces using low molecular mass p-coumaric, ferulic and sinapic acid as well as natural (acetosyringone) and synthetic 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) mediators as substrates. Oxygen consumption measurement, MALDI-TOF MS and SEC were used to follow the enzymatic reactions at pH 7, 8, 9 and 10 at 30°C and 50°C. Polymerization of lignins and lignan by S. ipomoea laccase under alkaline reaction conditions was observed, and was enhanced in the presence of acetosyringone almost to the level obtained with M. albomyces laccase without mediator. Reactivities of the enzymes towards acetosyringone and TEMPO were similar, suggesting exploitation of the compounds and low redox laccase in lignin valorization under alkaline conditions. The results have scientific impact on basic research of laccases.
authors: Departamento de Microbiología y Parasitología, Universidad de Alcalá, Ctra. Madrid-Barcelona, 28871 Alcalá de Henares, Madrid, Spain.
authors: Raquel
authors: R
authors: Moya
authors: Päivi
authors: P
authors: Saastamoinen
authors: Manuel
authors: M
authors: Hernández
authors: Anna
authors: A
authors: Suurnäkki
authors: Enriqueta
authors: E
authors: Arias
authors: Maija-Liisa
authors: ML
authors: Mattinen
mesh_terms: D000468:Alkalies / Q000494:pharmacology*; D002850:Chromatography, Gel; D005658:Fungi / Q000187:drug effects / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D042845:Laccase / Q000378:metabolism*; D017705:Lignans / Q000378:metabolism; D008031:Lignin / Q000737:chemistry / Q000378:metabolism*; D008970:Molecular Weight; D010084:Oxidation-Reduction / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects; D010636:Phenols / Q000378:metabolism; D058105:Polymerization / Q000187:drug effects; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013302:Streptomyces / Q000187:drug effects / Q000201:enzymology*; D013379:Substrate Specificity / Q000187:drug effects
chemical_list: D000468:Alkalies; D017705:Lignans; D010636:Phenols; D008031:Lignin; D042845:Laccase