BIOREMEDIATION OF AZO DYES BY NEWLY ISOLATED BACTERIA FROM CONTAMINATED SOIL OF NAJAFABAD

Background and Aim:Azo dyes are important contaminants of water and soil. In recent years, decolorization using microbial cells has been widely used. In this study the ability of isolated bacteria to use Pigment Red 48:2, Pigment Yellow 13 or Pigment Blue 15:3 as carbon source was investigated.Methods:Dye contaminated soil samples were collected near a textile factory in Najafabad. The ability of biodegradation was studied in Mineral Salt Medium (MSM) with 50mgL-1 of each azo dye. The initial pH was adjusted at 6.5. The medium was dispensed in 50 mL quantities into 250 mL erlenmeyer flasks. The flasks were cultivated in a shaker incubator at 200 rpm and 30°C. Thereafter, the optical density in 660nm were monitored at five hour intervals.Results:With increasing incubation time, a gradual increase in decolorization was observed. Pigment Red 48:2 was decolorized in the first 2 hours. Pigment Yellow 13 completely decolorized within 5 days and Pigment Blue 15:3 was completely decolorized within 7 days.Conclusion:These results are particularly showing the effectiveness of newly isolated bacteria for biodegradation of Pigment Red 48:2. Their decolorization power is better than many previous studies. The different results between the removal rates of dyes can be related to the structural differences of the dyes and metabolic pathways of bacteria in the bacterial consortium.

کلیدواژه ها:

bioremediation ، azo dyes ، bacterial consortium ، Mineral Salt Medium