eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2016-05-06 8 2 741 746 9559 article M. N. Abubacker 1 A. Ayesha 2 Department of Biotechnology, National College, Tiruchirappalli - 620 001 (India) Department of Civil Engineering, Kongu Engineering College, Perundurai, Erode - 638 052 (India). Azo-dye polluted soil samples were used for the isolation of bacterial species. Among the isolates Enterobacter aerogens, Proteus rettgeri, Pseudomonas fluorescens, and Staphylococcus aureus were the dominant bacterial species present and they are designated as indicator bacterial isolates. These indicator bacterial isolates are able to utilize the dye as nitrogen source and hence they are able to decolorize the azo-red and blue dyes. Decolourization was assayed colorimetrically at 540 nm for red and 580 nm for blue and percentage of decolourization was calculated. The optimum concentration for both the dyes was 100 ppm. The maximum decolourization of azo-red and azo-blue dye at the end of 96 hours of decolourization experiments were 90% and 80% respectively for consortium of indicator bacterial isolates. The individual bacterial isolates were less effective for decolourization. These bacterial consortium can be exploited as bioremediation agents to reduce dye pollutants. https://www.biotech-asia.org/vol8no2/decolourization-of-azo-dyes-by-bacterial-consortium/ Azo-red; Azo-blue dyes; Consortium; Decolourization; Bacterial isolates; Pollutant