Purification of a laccase from Marasmius quercophilus induced with ferulic acid: reactivity towards natural and xenobiotic aromatic compounds

In this study, we describe the biochemical features and the ability of a new laccase isoform from a Marasmius quercophilus strain collected on evergreen oak litter to transform various aromatic compounds. This laccase, induced with ferulic acid, exhibits interesting enzymatic properties, such as great thermal stability at 30 and 40 °C (24 h), no inhibition with EDTA, Cystein or SDS. These biochemical features are quite different from those observed with the laccase of another M. quercophilus strain collected in a different area of the South of France. Thus, this study shows the degree of variation in the properties of this enzymatic system within the same species. Furthermore we demonstrate that several natural aromatic compounds were transform leading to polymerization. The transformation of chlorophenols such as 2-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol is also observed without adding mediators (2,2′-azinobis(3-ethylbenzthiazoline-6-sulfonate) or 1-hydroxybenzotriazole) to the reaction mixture. Thus, the mediators used do not seem to extend the substrate range for this laccase under these experimental conditions.