Role of Ferrous Ions in Synthetic Cobaltous Sulfide Leaching of Thiobacillus ferrooxidans

AUTOR(ES)

Sugio, Tsuyoshi

RESUMO

Microbiological leaching of synthetic cobaltous sulfide (CoS) was investigated with a pure strain of Thiobacillus ferroxidans. The strain could not grow on CoS-salts medium in the absence of ferrous ions (Fe2+). However, in CoS-salts medium supplemented with 18 mM Fe2+, the strain utilized both Fe2+ and the sulfur moiety in CoS for growth, resulting in an enhanced solubilization of Co2+. Cell growth on sulfur-salts medium was strongly inhibited by Co2+, and this inhibition was completely protected by Fe2+. Cobalt-resistant cells, obtained by subculturing the strain in medium supplemented with both Fe2+ and Co2+, brought a marked decrease in the amount of Fe2+ absolutely required for cell growth on CoS-salts medium. As one mechanism of protection by Fe2+, it is proposed that the strain utilizes one part of Fe2+ externally added to CoS-salts medium to synthesize the cobalt-resistant system. Since a similar protective effect by Fe2+ was also observed for cell inhibition by stannous, nickel, zinc, silver, and mercuric ions, a new role of Fe2+ in bacterial leaching in T. ferrooxidans is proposed.

Documentos Relacionados

• Leaching of Zinc Sulfide by Thiobacillus ferrooxidans: Bacterial Oxidation of the Sulfur Product Layer Increases the Rate of Zinc Sulfide Dissolution at High Concentrations of Ferrous Ions
• Sulfide oxidation by spheroplasts of Thiobacillus ferrooxidans.
• Leaching of Zinc Sulfide by Thiobacillus ferrooxidans: Experiments with a Controlled Redox Potential Indicate No Direct Bacterial Mechanism
• Direct sulfide oxidation in the solubilization of sulfide ores by Thiobacillus ferrooxidans.
• Leaching of Pyrites of Various Reactivities by Thiobacillus ferrooxidans