Bio-degradation of reactive dyes by indigenous bacteria obtained from textile effluent contaminated site

Abstract

This experimental work deals with the degradation of textile dyes using bacterial species obtained from the effluent spilled soil site of CETP (Common Effluent Treatment Plant) in SIPCOT (State Industries Promotion Corporation of Tamil Nadu Limited), Perundurai. Reactive Red 120, Reactive Black 5 and Direct Red 81 were used as model dyes. Bushnell and Haas medium (BHM) was used to tests textile dyes degradation, initial screenings were carried out with the isolated 10 bacterial strains and the absorbance was measured spectrophotometrically and the (%) dye removal was calculated. Among 10 bacterial isolates, 5 bacterial isolates showed good synthetic dye degradation efficiency. The bacterial isolates were identified to be Bacillus subtilis, Bacillus cereus1, Bacillus cereus2, Bacillus megaterium and Pseudomonas fluorescens. Among five bacterial isolates Bacillus subtilis showed higher degradation efficiency on three synthetic reactive dyes. For Reactive Red 120 (36 %), Reactive Black 5 (44 %) and Direct Red 81 (59 %) were achieved. Bacterial consortium containing these five bacterial isolates was further explored and a maximal 80 % degradation of the three synthetic dyes was reached.