Anthraquinone dye assisted the decolorization of azo dyes by a novel Trametes trogii laccase

A new Trametes trogii laccase was purified and its biochemical properties were subsequently characterized. After a survey of other T. trogii laccases, this laccase showed a lower isoelectric point, different N-terminal sequence and kinetic parameters. Recently most laccase-catalyzed decolorizations of synthetic dyes are single-solute studies with commercially available dyes as model pollutants and need the employment of redox mediators. In this study, to simulate the real industry wastewaters, experiments of laccase-catalyzed decolorization of mixed dyes constituted by azo and anthraquinone dyes were carried out. The results showed that anthraquinone dyes, playing the role of mediators, dramatically promoted the degradation of azo dyes when there was no exogenous mediator in the reaction mixture. This study represents the first attempt to decolorize the mixtures of azo and anthraquinone dyes by purified T. trogii laccase, suggesting great potential for laccase to decolorize textile industry wastewaters.