Influence of Ni2+ and Mg2+ on the growth and activity of Cu2+-adapted Thiobacillus ferrooxidans

The ferrous ion oxidation ability of Cu2+-adapted Thiobacillus ferrooxidans strains affected by different concentrations of Ni2+ and Mg2+ in a Leathen medium was investigated. Cu2+-adapted strains have been developed through serial repeated subculturing. The level of tolerance of Cu2+-adapted strains to Ni2+ was improved in comparison with that of unadapted strains. The toxicity of Mg2+ to Cu2+-adapted T. ferrooxidans was almost the same as its toxicity to unadapted strains. The toxicity of ternary combinations of Ni2+, Mg2+ and Cu2+ to Cu2+-adapted strains was stronger than that of binary combinations of Ni2+ and Cu2+ or Mg2+ and Cu2+. Compared with unadapted strains, Cu2+-adapted strains exhibited better leaching efficiency in the bioleaching of nickel and copper from nickel-bearing pyrrhotite. (C) 2001 Elsevier Science B.V. All rights reserved.