Comparative Studies on Metal Biosorption of Cadmium and Silver by a Heavy Metals Hyperresistant Bacillus cereus

Abstract:

A heavy metals hyperresistant strain Bacillus cereus, HQ-1 with high resistance to Pb、Zn、Co、Cu、Cd and Ag was isolated from a lead-zinc mine. Minimal inhibitory concentration of Cd²⁺ for the bacterium was 1200 mg/L higher than others. The biosorption isotherms of cadmium on cells of Bacillus cereus strain HQ-1was investigated and compared with silver. It has a strong adsorptive capacity to the two metal ions．Its adsorption behavior could be described by either the Langmuir adsorption equation or the Freundlich adsorption equation. The adsorption mechanism of Cd²⁺ and Ag⁺ were studied by FTIR spectroscopic analysis and energy dispersive X-ray spectroscopy. We also simply located the resistant gene on the plasmid of the strain. The results of this study indicate that this Bacillus cereus strain has an excellent potential for biosorption and bioremediation of heavy metals pollution.