bio-removal of heavy metals using iron-oxidizing bacteria: a novel approach in environmental biotechnology

The pharmaceutical and hygienic productivity of wastewater containing pollutants, especially heavy metals such as nickel, andmercury are brought into the nature. recently, bio-removal of heavy metals has attracted significant attention as an eco-friendly approach for the research departments of the pharmaceutical companies. in the current study, removal of heavy metals including mercury and nickel was assessed using isolatediron-oxidizing bacteria from different sources. to this end, bacterial populations were isolated from a variety of aquatic ecosystems; including mahallat pond, mountainous rivers, iron industry wastewater, and treated industrial wastewater. the bacteria were cultured and purified in iron-oxidizing media after which the removal of mercury and nickel was measured through culturing the isolated bacteria in 3 different media of luria-bertani, phgii, and iron-oxidizing media containing the heavy metals (2 ppm). the results proved lb as a suitable medium for all the isolated bacteria in removing the heavy metals.it was shown that approximately 100% of the mercury was removed through the bacterial cultured in lb medium. the removal of nickel also reached its maximum of 30% by bacterial culture in lb medium. then, the phylogenetic study according to 16s rdna gene sequences showed thatthe isolated bacteria from iron industry wastewater was bacillus velezensis cr-502 (t).in summary, this study demonstrated the impressive ability of these bacteria for mercury removal and theeffects of different mediaon the removal of mercury and nickel.