Research On The Structure Of Microbial Communities Of Acid Mine Drainages Of Yinshan Lead-zinc Mine

Deep mining and surface mining of metal ores results in the contamination of ground and/or surface waters. The most well documented type of water pollution associated with mining is that which results from the accelerated oxidative dissolution of exposed minerals, principally sulfides, giving rise to acidic, metal-enriched waters generally referred to as "acid mine drainage" (AMD). Usually the acid mine drainage have a high concentrations of metal ions such as iron, copper, zinc and some nonmetal such as sulfur and arsenic. Despite the extreme acidity, heat, and high concentrations of sulfate and toxic metals, a diverse range of microorganisms populate AMD environments. These microorganisms can accellerate the generations of AMD, and result in the pollutions of environment. Also the microorganisms thrived in AMD that have a important significance in bioleaching, they can used to process the mineral and as a new source of bio-molecular in industry. So, study the microbial community and their functional activity of acid mine drainage have a great importance. In present study, we use RFLP technology based on the 16S rRNA and gyrB gene as the molecular marker to study the microbial compositions of Yinshan lead-zinc mine, Jiangxi province. And compared the difference of analysis result of two molecular marker. We also use the microarray that have been constructed and evaluated by our laboratory to detect the microbial community compositions and functional activities of Dexing copper mine and Yinshan lead-zinc mine and study the environmental factors how to influence the microbial community.Firstly, 16S rRNA genes were used as molecular marker to evaluate the diversity of microbial communities from three different AMD site in Yinshan lead-zinc mine. The result showed that the predominant microorganism in Yinshan mine were Cyanidium caldarium, Alpha-Proteobacteria, Gamma-Proteobacteria, Delta-Proteobacteria, Acidobacteria, Actinobacteria, Nitrospira. All three site have the high community diversity, C. caldarium is a red alga that can tolerate higher metal ions, it only presented in site YSK1, and Delta-Proteobacteria only presented in YSK2. Also we can only detected few Acidithiobacillus ferrooxidans which usually is the dominant populations in AMD, maybe this effected by the lower pH value. YSK2 and YSK3 have the similar environment factors and have a large different with YSK1 from chemical analysis result. From the phylogenetic analysis results both based on 16S rRNA gene, it suggested there are higher community similarity between YSK2 and YSK3 than with YSK1, this show that the distribution of the microbial communities was influenced by geochemical parameters, especially controlled by the iron, sulfur ions and pH values. And then we use the gyrB gene as molecular marker to carry out the diversity research and compare the analysis result by 16S rRNA. Dispite the microbial compositions have a similarity, we found the OUT number resulted from gyrB gene higher than 16S rRNA. The diversity index of gyrB gene also larger than 16S rRNA, but the microbial community abundance acquired from gyrB analysis was extremely higher than obtained through 16S rRNA analysis in terms of Shannon diversity index. Through gyrB gene, we will be able to differentiate closely related microorganisms in phylogenetic analysis, the result revealed that gyrB shows better performance in research concerning the correlation between community structure and geographic chemical parameters.Microarray technology has been widely used in researches concerning the function and structure of microbial community due to its unique advantages. We use the microarray that have been constructed and evaluated by our laboratory to detect the microbial community compositions and functional activities of the nine acid mine drainage samples of Dexing copper mine and Yinshan lead-zinc mine. At the same time we use the statistical methods such as detrended correspondence analysis (DCA), canonical correspondence analysis (CCA) and Partial CCAs to detect the dynamic influence of environmental factors to microbial community compositions and functional activity. A total of 373 genes (including 16S and functional genes) showed significant hybridization with at least one of the nine samples. These result indicated there have higher diversity and heterogeneity in AMD. These community composed by 19 different genus or species, including Acidithiobacillus ferrooxidans, Leptospirillum sp., Acidithiobacillus thiooxidans, Acidothermus cellulolyticum, Thermoplasmataceae archaeon, Sulfolobus, Sulfobacillus sp., Thiomonas sp., Hydrogenobacter acidophilus, Alicyclobacillus herbarius, Acidianus sp., Actinobyces naeslundii, Microthrix parvicella, Acidobacteria, Desulfobibrio longus, Acidiphilum spp., Holophaga sp., Thermomicrobium roseum and Metallosphaera sp.. The result by statistical and cluster analysis revealed the microbial community and funtion high influenced by the environmental factors(mainly are pH, Fe, Ca, Cu and S) .