Isolation and screening of azo dye decolorizing bacterial isolates from dye-contaminated textile wastewater

Azo dyes are released into wastewater streams without any pretreatment and pollute water and soil environments. To prevent contamination of our vulnerable resources, removal of these dye pollutants is of great importance. For this purpose, wastewater samples were collected from dye-contaminated sites of Faisalabad. About 200 bacterial isolates were isolated through enrichment and then tested for their potential to remove Remazol Black-B azo dye in liquid medium. Five bacterial isolates capable of degrading Remazol Black-B azo dye efficiently were screened through experimentation on modified mineral salt medium. Isolate SS1 (collected from wastewater of Supreme Textile Industry) was able to completely remove the Remazol Black-B dye from the liquid medium in 18 h. Further, the isolate showed the best performance at the dye concentration of 100 mg L^-1 medium (pH 7) and at temperature 35°C. Similarly, yeast extract proved to be the best carbon source for decolorization purpose. The results imply that the isolate SS1 could be used for the removal of the reactive dyes from textile effluents.