Different Leaching Efficiency and Microbial Community Structure Variation in Chalcopyrite Bioleaching Process Based on Different Initial Microbe Proportions

In order to investigate the effect of initial proportions of microorganisms on chalcopyrite leaching, six typical bioleaching strains were used to rebuild different co-culture systems. According to their different energy use types, Acidithiobacillus ferrooxidans DX2012 (ferrous and sulfur), Sulfobacillus thermosulfidooxidnas DX2012 (ferrous and sulfur), Leptospirillum ferriphilum DX12 (only ferrous), Ferroplasma thermophilum L1 (only ferrous), Acidithiobacillus caldus DX2012 (only sulfur), Acidithiobacillus thiooxidans A01 (only sulfur) were classified to construct four groups(cells): a, 1:1:1:1:1:1; b, 10:10:1:1:1:1; c, 1:1:10:10:1:1; d, 1:1:1:1:10:10. The results showed that leachate pH of consortium a, d firstly began to decline until stabilized at 1.4. On day 9th, Eh of consortium d began to sharply rise and finally stabilized at 720 mV. Compared with consortium a, b and c, copper concentration of consortium d increased to the highest level of 6000mg/L. All the evidence suggests consortium d is the best combination which held the highest leaching rate of copper. Real-time quantification polymerase chain reaction (RT-qPCR) was used to analyze the population dynamics during all the bioleaching process. Final microbial community structure of four consortia was trended roughly the same and consortium d was first to reach final community structure on day 27th. It is concluded that bioleaching co-culture system containing a higher proportion of sulfur-oxidizing bacteria works more efficiently.