Decolorization of Industrial Dyes by an Extracellular Peroxidase from Bacillus sp. F31

Abstract

An extracellular peroxidase purified from a bacterial strain Bacillus sp. F31 was evaluated for its ability to decolorize 16 different industrial dyes namely Bromophenol Blue (BPB), Reactive Yellow FN2R (RY), Congo Red (CR), Xylidine (XY), Methyl Orange (MO), Rhodamine B (RB), Erichrome Black Y (EB), Bismark Brown R (BBR), Basic Fuchsin (BF), Bismark Brown Y (BBY), Direct Violet 21 (DV), Direct Black 154 (DB), Methylene Blue (MB), Black RL (BRL), Coomassie Brilliant Blue R-250 (CBBG) and Malachite Green (MG). Each of these dyes was subjected to treatment with purified peroxidase (0.75 U) at 37o C for 30 min in phosphate citrate buffer (pH 5.2). Out of 16 different textile dyes the peroxidase efficiently decolorized five dyes out of which four are triphenyl methane dyes (BF, RB, CBBG and MG) showed decolorization up to (95.5, 70.8, 70 and 40 %) respectively, while a polymeric heterocyclic dye (MB) showed 66.2 % decolorization. These five dyes were studied further to enhance their decolorization by bacterial peroxidase by optimizing different reaction conditions (temperature, time, enzyme concentration, buffer pH, dye concentration and effect of various salt ions).