An evaluation into the biosorption and biodegradation of azo dyes by indigenous siderophores-producing bacteria immobilized in chitosan.

Abstract

The biodegradation and biosorption efficiency of an indigenous siderophores-producing bacterial community on azo dyes with immobilization in chitosan beads was evaluated in this study. 13 bacterial strains were isolated from textile wastewater streams. The bacterial strains were tested for the production of siderophores as well as their ability to decolorize toxic azo dyes in aqueous solution. Both qualitatively and quantitatively, all of the strains displayed high siderophores productivity. Furthermore, they displayed remarkable decolorization efficiency for azo dyes (Acid Black 1 and Reactive Black 5) in both free and immobilized form. The immobilization process was found not only to enhance the decolorization but also the degradation of azo dyes by the bacterial isolates. In a SEM micrograph, bacterial strains were immobilized, and the pores in chitosan bead to be trapped and adsorbed for dyes from synthetic wastewater. The extent of dye compounds degradation were examined using UV-visible and FTIR spectrophotometers on treated water samples and dye absorbed beads. After 72h of incubation, the UV-visible analysis revealed that the bacterial community could significantly reduce both azo dyes in wastewater by 90% at 300 mgL-1 dyes initial concentration. FTIR study confirmed the bonds of these dyes were broken to form less toxic chemicals via the bacterial community immobilized in chitosan beads. The immobilized bacterial community thus demonstrated effective approach of azo dye biosorption and biodegradation.