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Arsenic (As) is a quintessential toxic metalloid and it has been classified as Group 1 human carcinogen. The evolution of arsenic defense mechanisms due to the omnipresent nature of arsenic has resulted in its alteration to less toxic forms. The present study deals with the isolation of arsenic remediating microbial strains from soil samples and their integration into bioremediation strategy. From the metal contaminated site, 118 different bacterial strains were isolated from heavy metal contaminated site. Twenty-five strains were tolerant to arsenic and one bacterial strain Enterobacter cloacae (RSC3) demonstrated maximum growth at high concentration of arsenate (6000ppm). The cell growth kinetics of RSC3revealed the specific growth rate (µ) to be 0.55 h-1. The The bacteria hosts arsC gene in the genome involved in the reduction of arsenate to arsenite. AAS, SEM, TEM and EDX studies confirmed the arsenate transportation and efflux of arsenic by the bacteria. Furthermore, the strain showed multi-resistance to other heavy metals like zinc, cadmium, selenium and nickel and several antibiotics indicating its application for facilitating bioremediation of toxic metal contaminated sites. |
