The present study reports the successful and effective degradation of the persistent herbicide dymron catalyzed by the oxidative enzyme laccase in the presence of a reaction mediator (a laccase/mediator system).Using 2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as the mediator,over 90% of dymron was degraded within 24 h,while the half-life of dymron is 50 days in soil.The results suggested that oxidation of dymron resulted in the production of decomposed compounds with a single aromatic ring.We also found that edible surfactants and a dishwashing detergent were useful to solubilize dymron in an aqueous solution and did not inhibit the oxidative degradation.Degradation proceeded at acidic pH and in a broad range of temperatures (303-353 K).The use of natural mediators also allowed the oxidative degradation of dymron to some extent.In conclusion,we propose the possible use of a laccase/mediator system for the treatment of soils and drainwater contaminated with herbicides.
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