Decolourization of Textile Azo Dye Direct Red 81 by Bacteria from Textile Industry Effluent

Isolation and identification of the bacteria from textile effluent and evaluation of their ability to decolorize toxic sulfonated azo dye, Direct Red 81 were studied. A total of four bacterial strains were isolated from textile wastewater and their decolorizing activity was measured spectrophotometrically after incubation of the isolates for 24 h. in mineral salt medium modified with 100 ppm Direct Red 81 and supplemented with yeast extract. The bacterial strains were identified belonging to Raoultella planticola strain ALK314 (DR1), Klebsiella sp. SPC06 (DR2), Pseudomonas putida strain HOT19 (98.68%) (DR3) and Pseudomonas sp. strain 2016NX1 (DR4) respectively. Among the isolates Pseudomonas aeruginosa sp. strain ZJHG29 (DR4) was the most efficient bacteria to decolorize direct red 81 (100ppm) and showed 95% color removal efficiency at 36°C temperature in 24 hours. This study thus reveals that some bacteria inhabit in textile effluent whereby utilize the dyes as their source of energy and nutrition and imply their importance in the treatment of industrial effluents.