Pretreatment of Refractory Gold Ore by a Moderate Thermophilic Consortium in Stirred Tank Reactor

A moderate thermophilic consortium was enriched from acid mine drainage and coal mine wastewater samples collected in China. After adaptation to gradually increased pulp density of arsenic-bearing refractory gold ore and concentration of arsenic by serial sub-culturing for about two years, its tolerance ability was up to 200 and 8 g/L, respectively. After that, the consortium was employed to treat arsenic-bearing refractory gold ore to evaluate its ability and potential for industrial application. The results indicated that the maximum cell density was 2×109 mL-1 (the 14th day) during the whole process and arsenic extraction rate reached up to 59.93% in 22 d. Microbial diversity monitored by restriction fragment length polymorphism suggested that the consortium mainly consisted of four species, Sulfobacillus sp., Acidithiobacillus caldus, Ferroplasma thermophilum and Pseudomonas sp..