Analysis Of Microbial Communities In Mine Drainages Of Da Chang Lead-zinc Mine, And Influence Of Different Culture Conditions On Community

In nature,thermophiles and acidophiles are often found in acid mine drainage or hot spring.Deep mining of metal ores results in the contamination of ground and surface waters.The most well-known 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 contains high concentrations of metal ions such as iron,copper,zinc and some nonmetal such as sulfur and arsenic.Despite the extreme acidity and high concentrations of sulfate and toxic metals,a diverse range of microorganisms populate AMD environments.These microorganisms can accellerate the generations of AMD,thus make things worse.The microorganisms thrived in AMD have an important significance in bioleaching;they can be used to leach the mineral as a new source of bio-assistance in industry.Therefore,to study the microbial community and their functional activity in acid mine drainage has a great importance. In addition,mineral extraction processed by the microorganism is influnced by the concentration of metal ions,espesially the concentration of heavy metals,and the impact of different culture conditions.To study the impact of these factors to bio-eaching microbial community will enable us to optimize the application of bio-leaching and improve the efficiency of leaching.In present study,we use RFLP based on the 16S rRNA as the molecular marker to study the microbial compositions of lead-zinc mine,Dachang,Guangxi.What's more,we study the impact of different conditions of enrichment on 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 Dachang mine were Alpha-Proteobacteria, Gamma-Proteobacteria,Beta-Proteobacteria,Delta-Proteobacteria, Actinobacteria,Acidobacteria,Clostridia,Planctomycetes, Deinococcus,Bacilli&Nitrospira.2 sites have the high community diversity.Under different conditions,in 30℃to 45℃,enriched microbial community structure studies indicate that the enriched microbial mainly distributed in seven different branchs(Beta-Proteobacteria, Alpha-Proteobacteria,Gamma-Proteobacteria,Delta-Proteobacteria, Acidobacteria,Actinobacteria,Nitrospira),in different culture conditions with populations greater difference,this difference indicates that the the needs of temperature of microbes and the needs of different culture conditions.Furthermore,in high concentration(60 g/L)of nickel sulphate,with different energy resources,AMD(Acid Mineral Drainage)microbes was cultivated and selected.The microbial community diversity was then analyzed by PCR-RFLP technique.The result suggested that there are several kinds of bacterium,which are close to Firmicutes,Acidobacteria, and Proteobacteria in affinity respectively,can survive in high-concentration nickel ion.Furthermore,though there is different community diversity under different culturing condition,Acidiphilium and Acidithiobacillus are dominant species in the communities under different condition.This result can be an important theoretical guidance in study of nickel-bioleaching microbes and industrial practice.