重金属抗性菌HQ-1生物吸附镉与银的比较研究

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

摘要:

从北京市远郊东三岔地区一处废弃的铅锌尾矿中筛选到一株对铅、锌、铜、钴、银、镉等重金属均有很好抗性的蜡状芽胞杆菌Bacillus cereus HQ-1。特别是对镉的抗性高达1200 mg／L，具有很高的应用价值。比较研究了HQ-1菌株吸附重金属银和镉的情况与机理，发现该菌株对两种重金属离子都有较强的吸附能力。对镉的吸附行为符合Langmuir模型，对银的吸附行为符合Freundlich模型。通过红外光谱和X射线能谱对其吸附机理做了初步推断。并通过质粒消除试验证明该菌株的重金属抗性与抗性质粒存在有关。

关键词:镉，银，生物吸附，蜡状芽胞杆菌

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.

Key words:Cadmium, Silver, Biosorbent, Bacillus cereus