Optimization of fungal decolorization of azo and anthraquinone dyes via Box-Behnken design

Abstract

Dyes released by the textile industries pose a threat to environmental quality. Ligninolytic white-rot fungi can effectively decolorize colored effluents and conventional dyes. The present study investigates the ability of eleven strains belonging to Pleurotus, Ganoderma and Lentinula mushroom genera in the decolorization of eight textile azo and anthraquinone dyes added in solid-plate cultures. Pleurotus pulmonarius AMRL 177, showing the greatest decolorization ability, was further investigated for Remazol Brilliant Blue R (RBBR) decolorization using response surface methodology (RSM). RSM involved Box-Behnken design matrix for three design factors: dye concentration, nitrogen concentration and copper concentration were successfully employed for the optimization of four responses: lag time, mycelium extension rate, decolorization rate and laccase activity. Optimum values of responses obtained were: lag time 3 days, mycelium extension rate 2.8 mm d−1, decolorization rate 2.7 mm d−1 and laccase activity 480 U ml−1.