Community structure and dynamics of the free and attached microorganisms during moderately thermophilic bioleaching of chalcopyrite concentrate

A mixed culture of moderately thermophiles showed good performance in bioleaching of chalcopyrite. Its community structure was investigated by amplified ribosomal DNA restriction analysis. The result shows that Leptospirillum ferriphilum and Acidithiobacillus caldus were the predominant bacteria and Ferroplasma thermophilum, the only archaea, could be always detected during bioleaching. Therefore, real-time PCR assay was performed to monitor these microorganisms' dynamics in the solution and on the mineral surface. It is shown that both in the solution and on the mineral surface, A. caldus was the dominant species at the early stage and L. ferriphilum was the predominant species at the later stage. The amount of the same species exhibited different variation trends in the solution and on the mineral surface. The amount of attached L. ferriphilum increased faster than that of the free one, and the amount of attached F. thermophilum kept at a stable level while the free one increased rapidly at the end.