Variation in energy metabolism structure of microbial community during bioleaching chalcopyrites with different iron-sulfur ratios

The energy metabolism structure of microbial community plays an important role in the process of biohydrometallurgy. In this article, an artificial microbial community composed of three strains (Acidithiobacillus ferrooxidans, Leptospirillum ferriphilum and Acidithiobacillus thiooxidans) was used to leach three kinds of chalcopyrites with different iron-sulfur ratios. After 36 d of leaching, the chalcopyrite with iron-sulfur ratio of about 1:1 achieved the highest copper extraction (69.62%). In the early stage, iron oxidizing bacteria predominated, and the expression of rus and rio was 8 times higher than that in the late stage. In the late stage, sulfur oxidizing bacteria predominated, and the expression of tetH and HdrAB was 4 times higher than that in the early stage. Furthermore, the three bioleaching systems above were added with elemental sulfur (3 g/L); the chalcopyrite with iron-sulfur ratio of about 2:1 achieved the highest copper extraction (80.63%). The results suggest that the energy metabolism structure of the microbial community could be changed by changing the iron-sulfur ratio during the leaching process for improving the leaching efficiency of chalcopyrite.