Decolorization of Alizarin Red S Dye by Bacterial Strains Isolated from Industrial Effluents
Bioremediation of textile dyes has been of considerable interest because it is inexpensive, ecofriendly and produces a less amount of sludge. An attempt was made to evaluate the potential of two bacterial strains for decolorization of Alizarin red S were isolated from textile dye effluents. The bacterial strains Pseudomonas sp. and Escherichia coli were identified by morphologically and biochemically. Physico-chemical parameters like pH, temperature, dye concentration, carbon source, nitrogen source, combination of carbon source and nitrogen source and the effect of immobilized bacterial cells were optimized. The optimal condition for decolorization of Alizarin red S for both Pseudomonas sp. and Escherichia coli was found to be 1% glucose, 1% peptone, pH 7.0, 37°C, 500 mg/L dye concentration, combination of 1% glucose and 1% peptone and 50 immobilized bacterial cells per 100ml of Mineral Salt Medium. The highest decolorization rate was found to be 69.17% and 78.04 % for Escherichia coli and Pseudomonas sp. respectively. The results revealed that Pseudomonas sp. was found to be more efficient in dye decolorization than Escherichia coli.. The FTIR spectrum of control Alizarin red S displayed a peak at 3409.86 cm-1 indicates an OH stretching of phenols. Peaks at 2926.07, 1648.24, 1383.56 and 1066.10 showed CH stretching of alkanes, CC stretching of alkenes, nitro compounds and CO stretching of alcohols, ethers, carboxylic acids and esters respectively. The FTIR spectrum of the products formed after decolorization displayed a peak at 3448.24 showed OH stretching of phenols. Peaks at 1641.04 and 1080.47 indicate a CC stretching of alkenes.