Acidithiobacillus Ferrooxidans Culture Research Articles

A comparison of bioleaching of covellite using pure cultures of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans or a mixed culture of Leptospirillum ferrooxidans and Acidithiobacillus thiooxidans

The aim of this investigation was to determine the efficacy of covellite bioleaching using pure cultures of Acidithiobacillus ferrooxidans or Acidithiobacillus thiooxidans and a mixed culture composed of At. thiooxidans and Leptospirillum ferrooxidans. The experiments were carried out in shake flasks with or without iron(II) (1 g/L as ferrous sulphate) at pH 2.0. Inocula of both iron-oxidising bacteria were obtained from cultures with iron(II) as the sole energy source, whereas At. thiooxidans inoculum was taken from a culture growing on sulphur. The solubilisation of copper in flasks inoculated with At. thiooxidans was greatly enhanced in the presence of additional iron(II) achieving 62% copper extraction in 30 days. This result agrees with a mechanism proposed recently. On the other hand, the effect of supplemental iron was not so important for covellite leaching by the At. ferrooxidans culture and the mixed culture. Copper solubilisation by the At. ferrooxidans culture was nearly the same as that for the mixed culture (51% versus 55%).

Coupling bio-geochemical processes to regenerative energy for an industrial carbon cycle

The high turnover of carbon dioxide during bacterial oxidation of sulfides witnessed in cultures of Acidithiobacillus ferrooxidans, Leptospirillum ferroxidans, and even more efficient by Sulfolobus and other thermophile bacteria (e.g., Acidianus brierleyi), and the parallel rapid buildup of bacterial biomass suggests a coupling of these processes to solar energy in order to develop carbon dioxide cycling technologies for sustainable future applications. Synergistic effects can be expected with biometallurgical research and technology which also aims to further increase energy turnover reflected in higher leaching rates. The prospective technology has been investigated by growing bacteria on iron sulfide synthesized from iron sulfate using solar energy. A catalytic process was developed which allows sulfate to sulfide reduction at a carbon electrode at 120 °C. Photovoltaic energy is used to drive the electrochemical reaction and thermal heat for maintaining the operation temperature. H 2S is immediately converted in Fe 2+-containing solution to iron sulfide which is supplied to bacterial cultures for biological CO 2 fixation. It is estimated that solar-powered biohydrometallurgical processes for CO 2 fixation may reach efficiencies exceeding biological photosynthesis by one order of magnitude. In addition, they can be operated in infertile environments with very limited water. The bacterial biomass has a high quality and could be used for energy, materials, and even for food production. The perspectives and challenges for coupling biohydrometallurgical processes to regenerative energy utilization are discussed.

Formation of iodinin by a strain of Acidithiobacillus ferrooxidans grown on elemental sulfur.

The presence of the pigment iodinin, an Acidithiobacillus ferrooxidans culture metabolite, was demonstrated after growth of bacteria on elemental sulfur. The structure of iodinin was confirmed by X-ray structure analysis; its physiological role is discussed.