RESUMO
The main characteristics of a periodic bioleaching of the refractory gold-bearing pyrite ore from the Tandzut deposit (Armenia) with the help of moderate thermophilic bacterium Sulfobacillus thermosulfidooxi-dans subsp. asporogenes and original thermotolerant strains Leptospirillum spp. were studied. The optimal pH for oxidizing the ore by S. thermosulfidooxidans subsp. asporogenes was 1.8; the pulp density providing maximal iron leaching rate was 10%. The intensity of oxidation processes decreased at higher ore concentrations. When using S. thermosulfidooxidans subsp. asporogenes, the largest amount of iron passed into the solution at the initial oxidant (Fe3+) concentration of 1.3 g/l. Cocultivation of S. thermosulfidooxidans subsp. asporogenes and Leptospirillum spp. increased the degree of pyrite ore leaching to 98.4% vs. 34.1% in the case of the former bacterium alone.
