토착호산성박테리아의 적응기간에 따른 생물학적 용출 효율

Abstract

This study was carried out to leach the valuable metal ions from the mine waste ore using the adapted indigenous bacteria. First, collecting the indigenous bacteria in Goseong and Yeonhwa mine. polymerase chain reaction and 16S rRNA sequence were investigated to identify the indigenous acidophilic bacteria. In comparison sequences with the type strain of Acidithiobacillus ferrooxidans(ATCC 23270), the similarity of Goseong and Yeonhwa bacteria were obtained the range of 96.99-97.79% and 97.59-97.90%, respectively. The similarity of these bacteria were found 98.5% with the type strain of Acidithiobacillus ferrooxidans by using DGGE in the cluster analysis. Therefore, Goseong and Yeonhwa bacteria were considered Acidithiobacillus ferrooxidans. In order to tolerance the heavy metals, the indigenous bacteria were repeatedly subcultured in the adaptation-medium containing CuSO4ㆍ5H2O for 3, 6, 9 and 12 weeks, respectively. As the adaptation experiment processed, the pH was rapidly decrease in the adaptation-medium of 6, 9 and 12 weeks more than flat of the 3 weeks. The result of bioleaching use the adapted bacteria for 42 days, the pH value of the adaptation-medium in the 3 weeks tend to increased, whereas the pH of 6, 9 and 12 weeks tend to decreased. In decreasing the pH value in the adaptation-medium and in the leaching-medium, it was identified that the indigenous bacteria were adapted the Cu2+ ion and the mine waste ores. The contents of Cu and Fe in the leaching solution were usually higher leached in 6 weeks than 3 weeks due to the adaptation. Considering the bioleaching rates of Cu and Fe from these leaching solution, the highest increasing the efficiency metal ion were found to be Fe. Accordingly, it is expected that the more valuable element ions can be leached out from any mine waste, if the adapted bacteria with heavy metals are applied in future bioleaching experiment.