Characterization of heavy metals resistant bacteria isolated from a Cuban mining waste

Abstract

Environmental pollution by heavy metals is a contemporary world problem. Developing biotechnological strategies in remediation field has gained great attention in recent years for being more profitable, efficient and friendly to the environment. Heavy metal resistant bacteria are a powerful tool in bioremediation of metal contaminated environments. The aim of this study is to characterize heavy metal resistant bacteria, isolated from lateritic rubble, residual from Moa mining industry. Two bacteria (EL-1 and EL-2) were isolated from the lateritic rubble. The isolated ones were characterized and identified down to gender level. Resistance to nickel, cobalt, chromium and aluminum was evaluated in solid Tri minimal medium. The dose-response curve for nickel, cobalt, chromium and aluminum was determined, as well as the mechanism of bacterial resistance to nickel. In addition, antibiotic susceptibility was assessed. The two isolated were identified as Bacillus sp. The strains were resistant to all the evaluated metals, showing a high resistance to nickel (25 mmol-L-1). The Bacillus sp. EL-1 showed an induced mechanism of nickel resistance, while the Bacillus sp. EL-2 showed a constitutive resistance to this metal. The bacteria showed a predominance of sensitivity to the antibiotics evaluated. All these characteristics make them interesting to be applied in bioremediation strategies for environmental cleanup.

Keywords

• bacillus
• escombro laterítico
• resistencia a metales pesados
• biorremediación.