Microbial Degradation of Azo Dye by Pseudomonas spp 2413 Isolated from Activated Sludge of Common Effluent Treatment Plant

Abstract

In this study we intended to isolate and identify azo dye degrading and decolorizing bacterial strains as well as investigation its biodegradation mechanism. Different bacterial isolates were isolated from activated sludge of common effluent treatment plant and tested against Reactive Violet 5 (RV5) dye. The most potent isolate was identified as Pseudomonas spp via partial sequencing of 16s rRNA DNA. The decolorized sample showed lowering of peak to a smaller absorbance value for dye concentration of 200 mg/L, which informs that the decolorization is due to removal or degradation of dye. The comparison of TLC chromatograms before and after decolorization by Pseudomonas spp under UV light showed that the original dye was quite different from the supernatant obtained after dye decolorization, which was suggested by different values of retention factors obtained in the TLC experiment This difference confirms that decolorization was due to breakdown of dyes into unknown products. The identification of several degradation products from purified RV5 by Pseudomonas spp was achieved with FTIR spectroscopy, 1H NMR and GC-MS. The results showed four compounds, nitrobenzene, 4-nitrophenol, 4-nitroaniline, and 4-nitroanisole, as degradation products.