Roles of Oligotrophic Acidophiles (Alicyclobacillus) in Chalcopyrite Bioleaching System: Shake Flask Evaluation

摘要

An oligotrophic culture of acidophiles (Alicyclobacillus) isolated from Dexin acid mine drainage was evaluated for its synergistic effect in chalcopyrite bioleaching. Bioleaching of chalcopyrite with and without the Alicyclobacillus culture was investigated at different temperatures (33°C, 45°C and 65°C) and a culture-independent approach based on 16S rRNA gene clone library was used to analyze changes in the microbial community change during the bioleaching process. For 33°C leaching tests, only the bacterial community was analyzed, but for the other two temperatures, both the bacterial community and archaea communities were analyzed. Results showed that at high leaching temperature (65°C), Alicyclobacillus culture could increase copper leaching recovery from 57.83% to 60.7%. While at relative low temperature (45°C and 33°C), adding Alicyclobacillus culture inhibited copper bioleaching, copper leaching recovery decreased from 36.10% to 31.52% and from 34.02% to 21.97% respectively at 45°C and 33°C. Clone libraries analysis showed that Alicyclobacillus helps the growth of genus Sulfobacillus at 45°C while inhibiting the growth of genus Leptospillum at both 33°C and 45°C. Furthermore, when adding Alicyclobacillus growth of Ferroplasma was limited and Acidoplasma was facilitated at 45°C. At 60°C, adding Alicyclobacillus culture facilitated the growth of genus Metallosphaera while limiting the growth of Leptospillum and Ferroplasma. The results showed potential application of Alicyclobacillus in high temperature chalcopyrite bioleaching and bioremediation of acid mine drainage.