Immobilization of Acidithiobacillus ferrooxidans-1333 on the Waste Ore Particles for the Continuous Oxidation of Ferrous Iron

BACKGROUND: The biooxidation of ferrous iron has a great potential for the regeneration of ferric iron, in operations such as bioleaching, bioremediation. Many natural inorganic materials were investigated for use as supports immobilizing Acidithiobacillus ferrooxidans. The waste chalcopyrite is another natural inorganic material of which particles are easy to prepare from the leached out ore heaps and the source is abundant. OBJECTIVES: The aim of this work is to investigate several characteristics of the particles of waste ore that determines possibility of use as supports for immobilization of Acidithiobacillus ferrooxidans in the packed-bed bioreactor. MATERIALS AND METHODS: Acidithiobacillus ferrooxidans-1333 stored in Korean Centre for Culture Collection was used. The supports were prepared by sieving the particles of 5~30 mm in size out from the waste chalcopyrite ore heap. The cells were immobilized by the successive batch culture method and oxidation rate of the bioreactor was investigated in the continuous flow mode. RESULTS: The cell density of Acidithiobacillus ferrooxidans-1333 immobilized on the particles of waste chalcopyrite was 2.71×10(8) cells g(-1) and the highest oxidation rate of the packed-bed bioreactor was 3.65g.L(-1).h(-1). Oxidation rate of the bioreactor was less influenced by the concentration of ferrous and ferric iron in the input solution as well as by the aeration rate and dilution rate than other materials mentioned in other previous works. CONCLUSION: The waste chalcopyrite particle is efficient support material for immobilization of Acidithiobacillus ferrooxidans with comparable or superior characteristics to natural inorganic support materials reported before.