Influence diversity of extracellular DNA on bioleaching chalcopyrite and pyrite by Sulfobacillus thermosulfidooxidans ST黄铜矿与黄铁矿的生物浸出过程中 Sulfobacillus thermosulfidooxidans ST 胞外 DNA 的差异性研究

In this paper, Sulfobacillus thermosulfidooxidans ST was selected for use in bioleaching of pyrite and chalcopyrite. The adsorption experiments revealed that more cells were adsorbed on the surface of pyrite than on the surface of chalcopyrite. The role of extracellular DNA (eDNA) in the bioleaching process was investigated by depletion of eDNA using DNase I. The number of cells attached on the chalcopyrite and pyrite surfaces decreased on a large scale, and the lag phase of cell growth increased, causing the leaching percentages of pyrite and chalcopyrite to decrease by approximately 11.6% and 20.5%, respectively. The formation and distribution of eDNA secreted during bioleaching was assessed by a fluorescent dye-based method and visualized by confocal laser scanning microscopy (CLSM). The content of eDNA increased with bioleaching time. Furthermore, ST showed a stronger capacity to produce eDNA on the surface of pyrite than on the surface of chalcopyrite. These results showed that the removal of eDNA has a more significant effect on the bioleaching of chalcopyrite than on pyrite.