ABSTRACT
BACKGROUND AND OBJECTIVES: Heavy metals are considered as high risk biocides due to their harmful effects on human health, the environment and other living organisms. Bacterial strains showing resistance to heavy metals has been used for removing such toxic materials from the environment. In this study we isolated and characterized a heavy metals-resistance halophilic bacterial strains from Kal shoor Jovein of Sabzevar, one of the industrial zone of Khorasan-e-Razavi province in Iran and has naturally saline oils. MATERIALS AND METHODS: Strain JC-66 is heavy metals-resistance halophilic bacterial strains isolated from Kal shoor Jovein of Sabzevar. The 16S rDNA gene was sequenced to identify this bacterium. The appropriate conditions for its potency to remove the lead were tested in various temprature, pH and agitation speed. The resistance mechanism of JC-66 to lead were investigated. RESULTS: JC-66 is a Comamonas sp. according to 16S rDNA sequence analysis. Based on minimum inhibitory concentration (MIC) results, the isolated strain has high resistance to the lead metal. The optimal condition for lead removal was exhibited in neutral medium (pH 7) incubation temperature 37 °C, and shaking rate of 180 rpm for JC-66. X-Ray Diffraction results also are indicative of adsorption mechanism to lead metal uptake. Plasmid extraction was performed to confirm the role of plasmids in bacterial resistance to lead. CONCLUSION: It can be concluded that the mechanism of resistance to heavy metals in the studied strain, is the result of an expression plasmid, and adsorption. It was concluded that JC-66 is able to be one of the best candidates to remove industrial pollution because it showed high resistance to lead.
