Decolorization of Reactive Black 5 by Immobilized Bacterial Cells

Abstract

Azo dyes are xenobiotic contaminants that pose a substantial risk to environmental and human health. The study investigates biodecolorization potential of immobilized bacterial cells. Newly isolated bacterial cells were immobilized with two support matrices viz. sodium alginate and magnetite nanoparticles for the decolorization of model azo dye - reactive black 5. The bacterial cells coated with magnetic nanoparticles displayed complete decolorization of dye (100 ppm) in 16 h, while cells immobilized in sodium alginate beads required more time for complete removal of dye (24 h). Coated bacterial cells exhibited stable decolorization with repeated use for 12 cycles. However, due to destabilization of sodium alginate beads and subsequent cell leaching, stable decolorization was observed until 3rd cycle only. Nanoparticles coated bacterial cells offer the advantage of easy separation, allowing the cells to be reused for multiple cycles. Biodecolorized medium was analyzed by UV-Vis spectroscopy and FTIR techniques. The magnetic nanoparticles and coated bacterial cells were characterized through XRD and SEM, respectively. Overall results indicate that magnetite nanoparticles coated bacterial cells could be an effective tool for the decolorization of azo dyes.