Bacterial Isolation, Optimization and Immobilization for Decolorization and Degradation of the Azo Dye (Basic Red 46)

Dyes are the major toxic substances in all industrial wastewater and are highly carcinogenic to human beings and other soil and water living things. In this study, the most efficient bacterial isolate in decolorization of Basic Red 46 dye, isolate A3, was isolated and identified as Enterobacter cloacae sp. under the accession number KP202719. Different parameters such as dye concentration (100 to 4200 mg/L), pH (2, 4, 6, 7, 8 and 10), time (6 to 48hrs), shaking or static and temperature (25, 30, 37, and 45 degrees C) were optimized in the present study. It was found that Enterobacter cloacae sp. A3 decolorized 90% of BR46 dye (2000 mg/L) at pH 6 at 30 degrees C within 18 hrs under shaking condition and the minimum inhibitory concentration for strain A3 was 3600 mg/L. The immobilization of A3 in calcium alginate was more effective in dye decolorization than the using of free cells. The continuous fed batch decolorization study reported that the ability of immobilized strain A3 for the decolorization of repeated added 2000 mg/L of dye reach to 97.7%, 65% and 20.8% after three batch cycles respectively. This immobilized bacterial strain represents eco-friendly biosorbent for dye removal from colored industrial wastewater.