Decolorization kinetics of the azo dye Drimaren Blue X3LR by laccase

An extracellular Drimaren Blue X3LR decolorizing enzymatic activity was found in the crude filtrate of Funalia trogii grown by solid-state fermentation using wheat bran and soya bean waste. Decolorization of the azo dye Drimaren Blue X3LR by the crude filtrate and partially purified enzyme of Funalia trogii were investigated and compared. In the absence of additional redox mediator, maximum decolorization ratios of 81.33 % and 77.4 % were observed for Drimaren Blue X3LR using crude filtrate and partially purified enzyme respectively. Decolorization yield was found to be higher with crude enzyme preparations. Na2S2O5 inhibited laccase and dye decolorizing enzyme activities but a significant peroxidase activity inhibition was not observed. Since the reaction was catalyzed in the absence of H2O2 as co-substrate, it could be concluded that this enzyme is not a peroxidase but may be a laccase.. The kinetic parameters of decolorization were calculated according to Michaelis constant (Km of 1.700 x 10-5 mol dm-3 and Wmax = 8.02 x10-7 mol dm-3 sec-1).