以黄铜矿为主的低品位硫化铜矿生物浸出体系中的细菌优势菌群

Dominant Bacteria in Bioleaching System of Low-grade Copper Sulphide Ore Consisting Mainly of Chalcopyrite

通过对以黄铜矿为主的低品位硫化铜矿中温硫杆菌生物浸矿体系的细菌优势菌群的研究,探讨了黄铜矿的细菌作用机理.采用9K培养基从细菌浸出矿浆中分离出了14株中温硫杆菌,其浸矿能力都弱于分离前的自然混菌菌种,在浸矿过程中自然形成的混菌群落中各菌株之间存在着协同效应.从上述菌株中随机挑选出氧化浸出能力有较大差异的YK8,YK12和YK14进行了16SrDNA克隆测序分析,显示它们与Acidithiobacillus ferrooxidans的同源性均达到99%,为嗜酸氧化亚铁硫杆菌.由此说明该浸矿体系的优势菌群为嗜酸氧化亚铁硫杆菌,细菌氧化作用机理以直接作用为主.各纯菌株对Fe2+的氧化率存在较大差异,对菌浸矿浆用不同能源诱导培养后的混菌浸矿能力有显著变化.

In order to find out the reaction mechanism of bacteria with chalcopyrite, the dominant bacteria in a bioleaching system of low-grade copper sulphide ore consisting mainly of chalcopyrite were investigated. By using a 9K culture medium, 14 pure strains of mesophiles were isolated from leaching pulp of the ore. Copper leaching rates for these pure strains were all lower than those before isolation, indicating that there exists a synergistic effect among these strains of the domestic bacteria in the bioleaching process of the ore. By the sequence analysis of 16S rDNA, strains YK8, YK12 and YK14, which were randomly sampled from the 14 strains, were highly relative to Acidithiobacillusferrooxidans, with 99% sequence similarity, though they were very different in oxidation ability from each other. The three strains were identified as the species of Acidithiobacillus ferrooxidans, exhibiting the diversity of singleness of the bacterium community. The fact that the bioleaching system was dominated by the species of Acidithiobacillusferrooxidans indicates that the mechanism of bacterial oxidation is mainly direct reaction. There were marked differences in Fe^2＋ oxidation rate of various pure strains and notable changes in copper leaching rate for various bacteria induced by different culture media containing different energy SOurces.