Biodegradation of Novacron Turqueiose (Reactive Blue 21) by Pseudomonas aeruginosa

In the present study four bacterial strains Escherichia Coli, Salmonella typhi, Shiegella and Pseudomonas aeruginosa were used to evaluate their dye decolorization/degradation ability. Out of these bacterial strains Pseudomonas aeruginosa exhibited high potential for selected dye decolorization and hence it was used in subsequent experiments. The effect of dye concentration, pH, temperature, time, glucose and sodium chloride concentrations on decolorization were also studied to determine the optimal conditions required for maximum decolorization/degradation of selected dye by Pseudomonas aeruginosa. Maximum decolorization was observed at: 0.01 mg/L dye concentration, pH 10, temperature 45and#176;C, 0.1 mg/L glucose concentration, 0.1 mg/L sodium chloride concentration and 3 days incubation period at 37and#176;C. The metabolites formed after degradation by selected bacteria at optimum conditions were isolated and characterized by FTIR and mass spectrometry. In the mass spectra molecular ion peak was not observed and it was difficult to draw a conclusion from it. However, FTIR spectra provided some valuable information. The peaks at 1301.8 cm-1 for C-N and 1231.5 cm-1 for O-H stretch observed for original dye were completely absent in the decolorized products. The disappearance of C-N (part of the porphyrin ring system) peak in FTIR spectra shows that the porphyrin ring has been destroyed by bacteria. The extensive fragmentations in the mass spectra also confirm the degradation of the dye parental structure.