Biodecolorization of reactive black 5 using magnetite nanoparticles coated Bacillus sp. RA5

Abstract

Azo dyes are extensively used in various industrial sectors and their release into the surrounding contributes to the environmental pollution. In the present study, the bacterial cells coated with chemically synthesized magnetite nanoparticles were utilized for the biodecolorization of azo dye, reactive black 5 (RB5). The decolorization potential of immobilized cells was also compared with the free cells. At optimum experimental conditions, the complete dye removal was observed at 18 h by free cells whereas nanoparticle coated cells showed complete decolorization at 24 h for 100 ppm of RB5 dye concentration. UV–Vis spectroscopy and Fourier Transform Infrared Spectroscopy analysis of dye samples, before and after microbial treatment, confirmed the dye decolorization. The coated bacterial cells were able to decolorize the dye, efficiently, up to 12 cycles, confirming the reusability, stability and recyclability of magnetite coated bacterial cells.