Evaluation of Catalytic Efficiency of Coriolopsis caperata DN Laccase to Decolorize and Detoxify RBBR Dye

Application of enzymes for the removal of environmentally hazardous synthetic dyes from waste water has been considered eco-friendly and economic as compared with nonenzymatic techniques. In the present study, response surface methodology has been applied to decolorize and detoxify a recalcitrant and toxic anthraquinone dye Remazol Brilliant Blue R (RBBR) using Coriolopsis caperata DN laccase. Optimum concentrations of laccase, pH, and temperature for decolorization of RBBR dye (100 to 500 ppm) were 0.5 U ml−1, 3.5, and 40 °C, respectively. Result of RSM showed that optimum value of tested variables for maximum dye decolorization was 1 U ml−1 enzyme, 1000 ppm dye, and 60 min. Result of kinetic study showed that the K m, V max, K cat, and K cat/K m values for RBBR decolorization were 1.06 mM, 0.226 mM U−1 min−1, 135 S−1 and 1.27 × 105 S−1 M−1, respectively. The thermodynamic studies (Ea, 10.87 kJ M−1; ΔH, 7.408 kJ M−1; and ΔS, 80.06 J M−1 K) follow first-order kinetics, and the reaction is endothermic with a negative value of ΔG, suggesting spontaneous nature of reaction. The results of HPTLC, FTIR, and LC-MS analysis confirmed oxidative cleavage of N–H bond of RBBR dye by laccase. Treatment of laccase significantly reduced toxicity (phyto-, cyto-, and micro-) of RBBR dye. The present investigation confirmed C. caperata DN laccase as an efficient biocatalyst for bioremediation of textile dyes.