Efficient azoic dye degradation by Trametes trogii and a novel strategy to evaluate products released

Culture filtrates from the white rot fungus Trametes trogii were used for the degradation of two azo dyes: Xylidine and Methyl Orange. These culture filtrates showed a great potential for decolorizing even high concentrations of both azo dyes, without the addition of redox mediators, possibly due to the synergistic action of their high contents of laccase (104 U ml−1), accompanied by Mn-peroxidase (0.54 U ml−1), cellobiose dehydrogenase (0.45 U ml−1) and glioxal oxidase (0.38 U ml−1) activities. 75% of Methyl Orange (980 ppm) and 96% of Xylidine (480 ppm) were degraded after 24 h, degradation occurred after 6 days with a 94% of Xylidine removed (1440 ppm). Biodegradation products from Xylidine were determined by capillary electrophoresis followed by MALDI-TOF mass spectra. Neither aromatic amines nor colored quinones were detected, major metabolites being naphtalene sulphonate and xylene.

► Azo dye degradation by culture filtrates of a white rot fungus was studied.
► Higher degradation rates than literature values were achieved.
►  A novel strategy for characterization of dye degradation products is proposed.
► By capillary electrophoresis and MALDI mass spectra Xylidine products were identified.
► Final degradation products were naphthalene sulfonate and xylene.