Brazilian Journal of Microbiology Brazilian Journal of Microbiology
Braz J Microbiol 2016;47:39-46 - Vol. 47 Num.1 DOI: 10.1016/j.bjm.2015.11.013
Environmental Microbiology
Decolorization of azo dyes (Direct Blue 151 and Direct Red 31) by moderately alkaliphilic bacterial consortium
Sylvine Lalnunhlimi, Veenagayathri Krishnaswamy,
Department of Biotechnology, Stella Maris College, Chennai 87, Tamilnadu, India
Received 12 July 2014, Accepted 02 May 2015
Abstract

Removal of synthetic dyes is one of the main challenges before releasing the wastes discharged by textile industries. Biodegradation of azo dyes by alkaliphilic bacterial consortium is one of the environmental-friendly methods used for the removal of dyes from textile effluents. Hence, this study presents isolation of a bacterial consortium from soil samples of saline environment and its use for the decolorization of azo dyes, Direct Blue 151 (DB 151) and Direct Red 31 (DR 31). The decolorization of azo dyes was studied at various concentrations (100–300mg/L). The bacterial consortium, when subjected to an application of 200mg/L of the dyes, decolorized DB 151 and DR 31 by 97.57% and 95.25% respectively, within 5 days. The growth of the bacterial consortium was optimized with pH, temperature, and carbon and nitrogen sources; and decolorization of azo dyes was analyzed. In this study, the decolorization efficiency of mixed dyes was improved with yeast extract and sucrose, which were used as nitrogen and carbon sources, respectively. Such an alkaliphilic bacterial consortium can be used in the removal of azo dyes from contaminated saline environment.

Keywords
Alkaliphilic bacterial consortium, Azo dye, Direct Blue 151, Direct Red 31, Decolorization, Salinity
Braz J Microbiol 2016;47:39-46 - Vol. 47 Num.1 DOI: 10.1016/j.bjm.2015.11.013