Isolation And Molecular Diversity Analysis Of 9 Strains Of Acidithiobacillus Ferrooxidans

Acid Mine Drainages(AMD) result from the natural and biological oxidation of the sulfide minerals exposed in mining activities and cause severe environmental pollutions.These environments were characterized by extremely low pH,low concentrations of organic substances,high concentrations of metallic ions and sulfate.However,microorganisms are still observed in these harsh environments,mainly bacteria and archaea. The metabolism and interactions of these microorganisms play important roles in the formation of AMD.Thus,the isolation,cultivation and metabolic study of microorganisms that inhabiting in AMD environmentst is of great theoretical and application significance to bioleaching and bioextractiopn of metal such as copper and gold.As one of the dominant bacteria species in AMD,the isolation, identification and cultivation of Acidithiobacillus ferrooxidans are important tasks in research of bioleaching.As more and more strains of Acidithiobacillus ferrooxidans were being isolated from various AMD systems.Effective identification of these bacteria strains will significantly benefit the utilization and further research on the bioleaching important bacteria species.In this paper,9 strains of Acidithiobacillus ferrooxidans were isolated from sample taken from site Shuilongshan,a typical AMD in the Dexing copper mine,Jiangxi province,China.The basic physiological properties of the bacteria strains were characterized.Then, using molecular markers 16S rRNA gene and gyrB gene,and three functional genes encoding peripheral electron transporters:the rus gene, cyc1 gene and cycA-1 gene,as well as the whole genome rep-PCR,the molecular diversity of the 8 strains of Acidithiobacillus ferrooxidans and the Acidithiobacillus ferrooxidans type strain ATCC 23270 were studied. The result showed that,although 16S rRNA gene sequences were proven to be effective in identification of bacteria at the species level,its use in differentiating bacteria strains within one species is very limited. Sequence analysis of the three functional genes revealed little diversity. Only the sequence of rus gene and cycA-1 gene in the strain Y1a showed heterogeneity compared with the other strains,while the sequences of the other genes were 100%homologous to that of strain ATCC 23270. However,using the whole genome rep-PCR technology,greater heterogeneity were observed between the 9 strains of Acidithiobacillus ferrooxidans.Cluster analysis based on ERIC-PCR differentiated the 9 bacteria strains into 6 groups.