Mediator-assisted rhodamine B decolorization by Tramates versicolor laccase.

This study reported the decolorization of hazardous xanthenes dye, Rhodamine B by the Laccase Mediator System (LMS). Seven redox mediators were investigated in the mediators-assisted lacase catalyze oxidation reactions. Among redox mediators tested, 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) was the best one which gave the highest Rhodamine B decolorization for more than 80% within 48 h while only 20% achieved with no mediator added. In the laccase-ABTS mediator system, the best molar ratio of dye/mediator was 1:10 and dye/enzyme ratio was 0.5 micromol U(-1). The optimum conditions for Rhodamine B decolorization were at pH 4.0-5.0 and temperature 35-40 degrees C. The laccase-ABTS system could be a promising biotechnology developed for treatment of textile waste waters containing Rhodamine B.