Decolorization of synthetic dyes by white rot fungi, involving laccase enzyme in the process

In this study, decolorization of Remazol Brillant Blue Royal (RBBR) and Drimaren Blue CL-BR (DB) was investigated using three white rot fungi named as Pleurotus ostreatus (P ostreatus), Coriolus versicolor (C. versicolor) and Funalia trogii (E trogii). Decolorization studies were continued for 48 h under static conditions at 30 degrees C and pH 5.0. The degree of pH, dry mycelium weight (DMW), dye concentration, laccase activity and protein content were analyzed; the enzyme responsible for decolorization was detected for both dyes. Maximum and minimum decolorizations were obtained by E trogii and P. ostreatus, respectively. Both dyes at all concentrations were found to be toxic for P. ostreatus growth, whereas only DB above 60 mg/L was found to be toxic for C. versicolor growth. Maximum and minimum laccase activities were detected in decolorization media of F trogii and P ostreatus, respectively. Results of activity staining following SDS-PAGE showed that laccase is the only enzyme that is responsible for decolorization of DB and RBBR. (C) 2007 Elsevier Ltd. All rights reserved.