Optimization of Magenta Dye Decolorization Different Parameters by Citrobacter sp.

A thermo-alkalophilic bacterium Citrobacter sp. isolated from textile mill effluent sample as a decolouring microorganism. The maximum 500 mg L-1 Magenta (Basic Red-9) dye decolorization was takes place in 48 h and completely decolorizes the dye Magenta up to a maximum concentration 1000 ppm, however the time taken was 104 h. The optimum physical parameters such as temperature 40C, pH 8.0 and 2.5 % (w/v) of nitrogen source were required for the decolorization of Magenta dye by Citrobacter sp. Effect of seven different metal ions on decolorization of Magenta tested, in which most toxic was Cadmium and less toxic was Lead at 0.05 mM concentration. The curing study indicates that decolorization was takes place by enzyme which was plasmid mediated. The degraded dye metabolites are analyzed by TLC and diazotization, carbylamines test for individual metabolite indicates biotransformation of Magenta into aromatic amine and non-toxic aromatic metabolites. These results suggest that the isolated organism Citrobacter sp. as a useful tool to treat waste water containing reactive dyes at static condition.