Decolorization of direct blue: 14 dye by thermoalkalophilic aerobic bacillus sp.

Abstract

A thermo-alkalophilic bacterium isolated from textile mill effluent samples and identified as a Bacillus sp., on the basis of biochemical tests. The selected bacterium showed high decolorization activity in static condition as compared to shaking condition and the maximum 1000 mg l-1 Direct Blue-14 dye decolorization was takes place in 72 h. The optimum physical parameters such as temperature 40-50 °C, pH 8.0 with 2.5% (w/v) of nitrogen source and 4% (w/v) glucose were required for the decolorization of Direct Blue-14 from this bacterium. UV-Visible analyses and colorless bacterial cells suggested that Bacillus sp. exhibited decolorizing activity through biodegradation, rather than inactive surface adsorption. The degraded dye metabolites are analyzed by TLC and diazotization, carbylamines, Ames test for individual metabolite indicates biotransformation of Direct Blue-14 into aromatic amine and non-toxic aromatic metabolites. These results suggest that the isolated organism Bacillus sp. as a useful tool to treat waste water containing azo dyes at static condition. © 2016 by IGI Global. All rights reserved.