重金属对其铁氧化能力影响的评估
(1. 湖南科技大学 生命科学学院，湘潭 411201；2. 中南大学 资源加工与生物工程学院，长沙 410083)
摘 要: 采用稀释分离法，从山西中条山铜矿的酸性矿坑水中分离出一株铁氧化细菌，命名为ZTS菌株。该菌株为革兰氏阴性细菌，螺旋状或弧状，最适生长温度为30 ℃，最适生长pH值为2.5，对低浓度的酵母浸出物较敏感。形态学和生理学分析表明，ZTS菌株可能属于钩端螺旋菌属的成员；16S rDNA序列的系统发育分析表明，该菌株与氧化亚铁钩端螺旋菌典型菌株ATCC 49879位于系统发育树的同一分支，相似度为100%，从而证实ZTS菌株属于氧化亚铁钩端螺旋菌。考虑到当前的商业利益，考察了Cu2+、Co2+ 和Ni2+对ZTS菌株氧化亚铁能力的影响。结果表明：3种金属对ZTS菌株的毒性强弱依次为Co2+＞Cu2+＞Ni2+。就Ni2+抗性能力而言，ZTS菌株能够耐受Ni2+的浓度高达160 mmol/L，这比已报道的氧化亚铁钩端螺旋菌的Ni2+抗性能力要强得多，这种能力可能与它的遗传特性有关。
关键字: 酸性矿坑水；氧化亚铁钩端螺旋菌；铁氧化能力；重金属抗性
（1. School of Life Science, Hunan University of Science and Technology, Xiangtan 411201, China;
2. School of Resources Processing and Bioengineering, Central South University, Changsha 410083, China）
Abstract:Using a dilution method, an iron-oxidizing bacterium, designated strain ZTS, was isolated from acid mine drainage of Zhongtiaoshan Copper Mine, Shanxi Province, China. Cells of strain ZTS were spiral or curved-shaped, gram-negative, and the optimum temperature was 30 ℃ and the optimum pH was 2.5. The strain ZTS was sensitive to low concentration of yeast extract. The cell shape, physiological characteristics and 16S rDNA sequence analysis indicated that the strain ZTS should belong to the species of Leptospirillum ferrooxidans. Considering its recent commercial interest, the effects of copper (Cu2+), cobalt (Co2+) and nickel (Ni2+) on strain ZTS were investigated during the oxidation of a ferrous iron solution (40 g/L). The results show that copper, cobalt and nickel individually inhibit the ferrous iron oxidation in the order Co2+＞Cu2+＞Ni2+. Interestingly, the nickel resistance capability of strain ZTS, which can resist nickel of 160 mmol/L, is much stronger than that of Leptospirillum ferrooxidans reported ago. This ability of strain ZTS may be relevant to its genetic characteristics.
Key words: acid mine drainage; Leptospirillum ferrooxidans; iron oxidation ability; heavy metal resistance
