Study on azo dye congo red biodegredation by isolated bacteria from textile effluent

Azo dyes are released into wastewater streams without any pretreatment environments. To prevent contamination of our vulnerable resources, removal of these dye pollutants is of great importance. Traditional methods of treatment are found to be expensive and have operational problems. Biological decolourization has been investigated as a method to degrade azo dyes .
For this purpose, wastewater samples were collected from dye-contaminated sites to isolate Congo red decolourizing bacteria. one strains were obtained with potential for Congo red decolourization. On primary screening, an aerobic gram positive bacillus was found to have maximum observable Congo red decolourization activity.
Different parameters such as various carbon source, nitrogen source, inoculum size, temperature and pH were optimized for decolourization of Congo red by using bacterial isolates. pH, nitrogen source and inoculum size were found to be most effective in dye decolorization.
Enhanced decolourization was observed in presence of xylose as a carbon source and yeast extract as a nitrogen source.The optimum of inoculum size was found to be 5%. The optimum pH obtained for decolourization of Congo red by bacteria strains was 5.0. The optimum temperature was found to be 250C. under optimal conditions maximum decolourization percentage was about 100%.
High decolorization extent and facile conditions show the potential for this bacterial strain to be used in the biological treatment of dyeing effluents. The results reported here warrant further investigation to establish the usefulness of these isolates for biodegradation application such as waste water treatment.