Microbial Diversity In Acid Mine Drainage At Tong Lushan Copper Mine

Acid mine drainage (AMD) was acidic and generally enriched with iron, aluminum, sulfate and heavy metals such as copper, zinc, arsenic, gold, silver, lead, cadmium and so on. Acid mine drainage was one of the most hazardous types of water contamination due to its nature, extent of contamination and difficulty of treatment. Acid mine drainage was caused by the oxidization of the sulfide minerals and the speed of the oxidation could be accelerated up to a hundred times by the action of bacteria which could be screened and used for bioleaching. The geochemical conditions of the acid mine drainage were highly variable from site-to-site and the community compositions reflected this change in geochemical conditions. To better understand the acid mine drainage and the microbial composition structure, we characterized the microbiology of samples from the Tong Lushan Copper Mine in Daye, Hubei province, China.Samples including sediment covered by the acid mine drainage and acid mine drainages in three sites at Tong Lushan Copper Mine were collected. By using the technique of PCR-RFLP and the reconstruction of the 16S rDNA clone library, the microbial diversities in acid mine drainage and the sediment were revealed in this study. The geochemical properties were also examined for the distributions and associations of microorganisms were influenced on the geochemical conditions in acid mine drainage environments.PCA analysis based on the geochemical properties of sites showed that tls1 and tls2 had similar geochemical properties and tls3 had a different geochemical property comparing to the other two sites.RFLP analysis showed that there were respectively 14, 11, 19 operational taxonomic units (OTUs) found in the bacterial clone library of tls1, tls2 and tls3. The OTUs was 6 in the archaeal clone library of tls2 and 12 in the bacterial clone library of the sediment of tls2.Phylogenetic analysis revealed that the main bacterial compositions in the acid mine drainage of tls2 were A. ferrooxidans and L. ferrooxidans and the main archaeal composition in the acid mine drainage was Thermoplasma. Analysis of the microbial composition in the sediment of tls2 showed that the main microbe was Acidiphilum and Methylocella-like bacteria. Phylogenetic analysis also revealed the diversity among the three acid mine drainage. The majority of the clones in tls1 and tls2 clone libraries were related to A. ferrooxidans within the gamma-Proteobacteria and L. ferrooxidans within the Nitrospira while clones in tls3 clone library mainly fell into the divisions of alpha-Proteobacteria and gamma-Proteobacteria (but not clones in tls3 were related to A. ferrooxidans).The PCA based on the six divisions (the gamma-Proteobacteria, alpha- Proteobacteria, Nitrospira, Acidobacteria, Actinobacteria and the delta-proteobacterium) showed that tls1 and tls2 had a comparatively close microbial community structure and tls3 had a significantly different microbial community structure from the other two sites.In conclusion, the diversity in the acid mine drainage was very low. The microbial compositions between the sediment and the acid mine drainage were different. Combined with the PCA analysis and the phylogenic analysis, we revealed that sites which had similar biogeochemical properties had similar microbial communities.