Azo dyes constitute the largest and most versatile class of synthetic dyes used in the textile, pharmaceutical, food and cosmetic industries and represent major components in wastewater from these industrial dying processes. The present investigation includes study of bacterial isolates from water samples collected from three sources viz., Industry, Lake and Sewage. The bacterial isolates were then screened for the dye decolorizing ability in Mineral salt media (MSM) broth amended with 5ppm of Crystal violet and Bromophenol blue. Bacterial isolates G and H were found capable of degrading both Crystal violet and Bromophenol blue dyes to a greater extent within 120 hours of incubation. The decolorization potential of the two isolates G and H were investigated at different operational parameters like, Dye concentration, pH, Temperature, Carbon sources and Nitrogen sources. Among two isolates, isolate G showed considerably high percentage decolorization of Crystal violet and Bromophenol blue at 50ppm, 100ppm and 150ppm repectively. The isolates, G and H showed high decolorization at pH 8 and 5.6 within 120 hours of incubation for Crystal violet and Bromophenol blue. The isolate G and H were identified as Pseudomonas sp. and Salmonella sp. respectively based on morphological and biochemical characterization. The present investigation revealed these isolates can be used for treatment of effluents contaminated with Crystal violet and Bromophenol blue.
