Decolorization and biodegradation of textile azo dye Acid Black 24 by developed bacterial consortium CN-1A

Abstract

Biological treatment of waste water seems to be a promising option for the treatment of dye containing effluent. A consortium of organisms proves to be more effective rather than individual organism in the process of degradation. The present investigation tries to develop a novel bacterial consortium CN-1A consisting of <em>Moraxella osloensis</em>, <em>Pseudomonas aeruginosa</em>, <em>Citrobacter freundii</em>, <em>Bacillus </em>sp. and <em>Bacillus thuringiensis</em> for the decolourization of Acid Black 24 (AB 24), a diazo dye used in textile industries. This consortium efficiently removed 84% of the 50 mg/L of dye from the mineral salt medium. The rate of decolorization was found to increase up to 20 h of incubation, after which there was a gradual decrease. The degradation reaction followed first order kinetics with a k value of 0.1796 h^-1 with R² value of 0.968. The FTIR and GC-MS analyses indicated aniline, naphthoquinone and salicylic acid as intermediate compounds in the dye degradation by developed consortium CN-1A. This consortium was found to be capable of bringing about 79.72% degradation of 80% diluted textile effluent containing 15 mg/L of AB 24. Phytotoxicity studies clearly indicated the efficiency of this treatment process, which may pave way for the reusability of dye containing effluent.