Insights into the effect of external species introduction on pyrite bioleaching

摘要

The effects of external species introduction to an artificial single strain leaching system were investigated in the laboratory. In this experiment, Acidithiobacillus caldus or Leptospirilum ferriphilum, serving as external species were introduced at different time points to six artificial single strain leaching systems that use L. ferriphilum or A. caldus respectively as the sole original strain. The result showed that leaching abilities of all treatments significantly increased following the introduction of an external species. The increasing degrees of leaching ability were the most significant in treatments that have external species introduced at mid-exponential growth phase. The increasing degrees of leaching ability were the least significant in treatment that introduced external species at early-exponential growth phase. To further explore the relationships between copies of leaching bacteria and leaching abilities, population dynamics of all strains were also monitored throughout the process. When external species were introduced at lag and early-exponential growth phases, growths of original strain were seriously inhibited. But growths of strains were not seriously affected when external species were introduced at the mid-exponential growth phase.