Changes of microbial diversity during pyrite bioleaching

Microorganisms, one of the key factors affecting the bioleaching process, change the components of extracellular polymeric substance (EPS) and community structure to survive in leaching environments. In this work, Fourier transform infrared (FTIR), X-ray powder diffraction (XRD) and 16S rDna high-throughput sequence analyses were used to reveal the microbial changes in planktonic and sessile phases during bioleaching. The results showed the occupation of sessile cells decreased from 66.2% to (10 +/- 3)%. After bioleaching, the planktonic and sessile cells have similar EPS, but they are different from the original cells. Pyrite dissolution mainly occurs at the early and late stages with the decreasing of particle diameter, by 50% and 40%, respectively. The 16S rDna gene based sequence analysis results in total of 1117420 Reads across the six samples, presented among 7 phyla, 9 classes, 17 orders, 23 families and 31 genera. GeneraLeptospirillumandSulfobacillusare the main bacteria at the early and middle stages, andLeptospirillumis the main genus at the end of bioleaching.AquabacteriumandAcidovoraxare special genera in sessile cells andWeissellais special in planktonic ones.