The interaction of acidophiles driving community functional responses to the re-inoculated chalcopyrite bioleaching process

Re-inoculation was an effective way to improve bioleaching efficiency by enhancing the synergetic effects of biogenic Fe 3+ coupling with S 0 oxidation. However, the complex microbial interactions after re-inoculation have received far less attention, which was crucial to the bioleaching performances. Herein, the enriched ferrous oxidizers (Fe O) or sulfur oxidizers (S O) were inoculated to chalcopyrite microcosm, then they were crossly re-inoculated again to characterize the interspecific interaction patterns. The results showed that the dominant species in Fe groups were Acidithiobacillus ferrooxidans , while A. thiooxidans predominated in S groups. Introducing Fe O resulted in a great disturbance by shifting the community diversity and evenness significantly ( p < 0.05). In comparison, the communities intensified by S O maintained the original composition and structures. Microbial networks were constructed positively and modularly. The networks intensified by Fe O were less connected and complex with less nodes and edges, but showed faster responses to the re-inoculation disturbance reflected by shorter average path length. Interestingly, the genus Leptospirillum were identified as keystones in S groups, playing critical roles in iron-oxidizing with lots of sulfur oxidizers. The introduced sulfur oxidizers enhanced microbial cooperation, formed robust community with strong bio-dissolution capability, and harbored the highest bioleaching efficiency. These findings improved our understanding about the acidophiles interactions, which drive community functional responses to the re-inoculated bioleaching process. • Microbial interactions during the intensified chalcopyrite bioleaching were analyzed. • Introducing enriched ferrous oxidizers caused great disturbance to the microcosms. • Leptospirillum was the keystone to oxidize irons when sulfur oxidizers were dominant. • Sulfur oxidizers enhanced microbial cooperation in reconstructed robust community.