Improved leaching performance of chalcopyrite by microbial cultures subjected to mutation

摘要

To obtain microbial cultures with the ability to efficiently leach copper ion from chalcopyrite, microbial samples from acid mine drainage sites were mixed and then subjected to mutation using sodium nitrite (NaNO_2), diethyl sulfate (DES), ultraviolet light (UV) and their combinations. Mixed cultures with a much stronger ability to leach copper ion (identified as mixed cultures A, B, C, D and E) were obtained by screening on leaching media. Leaching tests showed that mixed culture E had the best leaching performance and increased the Cu~(2+)content by 120.5 percent in 20 days, compared to a control without mutation treatment. Mixed culture E grows well on heathen leaching medium supplemented with Cu~(2+) (at a final concentration of 32 g/L), reaching 3.2 X 10~7 cells/L after 15 days, while the unmutated control culture cannot survive beyond 15 days, indicating that mixed culture E is more tolerant of high concentrations of Cu~(2+). In addition, continuous leaching by mixed culture E is very effective at a pulp density of 1 percent. These results suggest that it has the potential for industrial applications.