The development of CotA mediator cocktail system for dyes decolorization

AIMS: The increasing use of dyes leads to serious environmental concerns, it is significant to explore eco-friendly and economic approaches for dye decolorization. This study aimed to develop mediator cocktail (AS and ABTS) for enhancing the capability of laccase-mediator system in the removal of dyes. METHODS AND RESULTS: By mediator screening, the mediators of ABTS and AS (ABTS, 2, 2'-azino-bis-(3-ethylbenzothiazo-thiazoline-6-sulphonic acid); AS, acetosyringone) were combined for dyes decolorization. The Box-Behnken Design and response surface analysis was performed to optimize experiment conditions. Comparing the CotA-ABTS-AS cocktail system with CotA-single mediator system showed that the coupling of ABTS and AS could increase the decolorization rate 15 times higher, save a third of the cost and shorten the reaction time by 50%. In addition, our studies revealed that sequential oxidation may occur in CotA-ABTS-AS system. CONCLUSIONS: Compared with CotA laccase-single mediator system, the CotA-ABTS-AS cocktail system showed advantages including higher efficiency, lower cost and shorter reaction time. SIGNIFICANCE AND IMPACT OF THE STUDY: This was the first report on the dyes decolorization by laccase mediator cocktail system. These results paved the curb for the application of laccase mediator system in various industrial processes.