【作者】 冯光志；

【导师】 黄巧云；

【作者基本信息】 华中农业大学 ， 土壤学， 2009， 硕士

【摘要】 嗜酸氧化亚铁硫杆菌（Acidithiobacillus ferrooxidans,简称A.ferrooxidans）能氧化亚铁离子和还原性硫实现金属离子的溶浸作用,是浸矿过程中起主要作用的细菌。本文选取铜绿山与石头嘴古铜矿区域酸性矿坑水,筛选高活性铁氧化细菌,进行了16S rDNA分子鉴定、生理生化特征分析及重金属抗性研究,并利用该菌株对云南、安徽、大冶等地的低品位氧化-硫化混合型铜矿石进行了摇瓶浸出试验。主要结果如下:1.在初步的富集实验中,共获得8株铁氧化细菌,进一步进行二次筛选,得到氧化活性最高的菌株SY。2.对菌株SY的16S rDNA进行扩增、克隆、序列测定和同源性分析与序列比对,发现其与氧化亚铁硫杆菌菌株（DQ 062116.1）最为相似,鉴定该菌株为氧化亚铁硫杆菌。3.生理生化性质测定表明,菌株SY的最适生长温度为30℃,最适pH值为2.0,接种量对亚铁离子完全氧化时间影响不大。4.菌株SY对Cu²⁺、Cd²⁺、Ni²⁺、Zn²⁺等重金属离子抗性的最低抑菌浓度分别为300、350、700和800 mmol/L,对多种重金属离子均显现出很高的抗性。对该菌株经过约一个月的驯化,在400 mmol/LCu²⁺离子的环境下,48小时内能完全氧化亚铁离子。5.利用菌株SY对湖北大冶、云南丽江及安徽枞阳等地的氧化-硫化混合型低品位铜矿石进行的20天浸出实验显示,细菌浸出比酸浸Cu²⁺的回收率高出近30%,表明该菌株在硫化矿浸出中具有较好的应用前景。另外,在生物浸出过程中,菌株SY对湖北大冶、安徽枞阳、云南丽江等地的低品位矿样的浸出率分别为84.28%、74.38%、33.31%。通过与相关文献中使用的氧化亚铁硫杆菌菌株比较,菌株SY对多种重金属表现出很高的抗性,非常符合多金属复杂矿的浸出要求,表现出较好的应用价值。SY菌对大冶地区混合型铜矿石浸出结果表明土著分离的菌株在本土矿石生物浸出中能显示出很大的优势。更多还原

【Abstract】 Acidithiobacillus ferrooxidans can oxidize ferrous ions and reductive sulfur and results in metal ions leached, it is considered to be the major bacterium in the course of leaching. In this dissertation, firstly, acid mine drainage from tonglv mountain and shitouzui ancient mine area were collected for the isolation and purification of high active Acidithiobacillus ferrooxidans and the 16S rDNA of the isolate was analyzed. Secondly, we study the physiological property and determine the decree of resistance of strain SY to Cu²⁺, Cd²⁺, Ni²⁺, Zn²⁺. Lastly, bioleaching experiments with strain SY to the low-grade oxide - sulphide mixed copper ore collected from yunnan、anhui and daye were studied and discussed.In the initial enrichment experiment, eight strains of iron-oxidizing bacteria were isolated. Ferrous iron oxidation activity was measured as the second screening for these isolates. Strain SY was the most active on ferrous iron oxidation among the Acidithiobacillus ferrooxidans strains tested and selected for further study.The 16S rDNA fragments of strain SY was amplified, cloned, sequenced and homologous analysis. It revealed that the strain SY was closely related to Acidithiobacillus ferrooxidans （DQ 062116.1）. Therefore it is accepted that strain SY is Acidithiobacillus ferrooxidans.The physiological and biochemical characteristics analysis showed that the optimal growth pH and growth temperature was about 2.0 and 30°C respectively. But the whole time of ferrous ions complete oxidation was not heavily affected by the inoculation.Experiments about heavy metal resistance of strain SY show that the MTC values were: 300, 350, 700, 800 （mmol/L） to Cu²⁺, Cd²⁺, Ni²⁺, Zn²⁺ and it demonstrate a high resistance. In addition, after the domestication about a month, the copper-adapted strain was able to complete oxidation ferrous ions at 400 mmol/L Cu²⁺ with 20% （v/v） inoculation amount in two days.Bioleaching experiments with strain SY to the low-grade oxide - sulphide mixed copper ores collected from Yunnan、Anhui and Daye in Hubei reveal that bacterial leaching with a high recovery rates nearly 30% than acid leaching after leaching about 20 days. It indicates that the strain has good application prospects in the leaching of sulfide minerals. In addition, the extraction rate were 84.28%.. 74.38%、33.31% from Yunnan、Anhui and Daye core sample in bio-leaching process respectively.Compared with the relevant literature about strains of Acidithiobacillus ferrooxidans, we can see that strains SY with a relatively high resistance to some heavy metal is able to meet the leaching requirements of complex multi-metal ore. It indicates that the strain has a good application prospect. The leaching result of mixed copper ore in Daye region by strain SY showed that indigenous strains can show a lot of advantages in the bioleaching of ores.更多还原