Removal of Mixed Azo Dyes by a Moderately Alkaliphilic Bacterial Strain Isolated from Textile Effluent Contaminated Site

The aim of the present study was to isolate an alkaliphilic bacterial strain from textile effluent contaminated site and to investigate the ability of the bacterial strain to decolorize the mixed dyes, Direct Brown MR and Direct Yellow SG at different concentrations. The enriched moderately alkaliphilic bacterial strain could decolorize mixed azodyes (DB MR and DY SG) at different concentrations (50 to 250 mg/L). The bacterial strain exhibited maximum decolourization ability of mixed dyes at pH 9, at a concentration of 150 mg/L (90%) of DB MR and DY SG which showed the maximum degradation of 90% by the end of 5th day, at an optimum temperature at 28 °C. Supplementing the media with sucrose and yeast extract, as carbon and nitrogen source could enhance the dye decolourization efficiency of the isolated bacterial strain. The isolated mixed dye degrading bacterial strain was identified by 16S rRNA sequencing as Serratia marcescens. Such isolated bacterial strain could be applied to biological systems for the effective removal of these mixed dyes from textile effluent wastewater.