IRON AND SULFUR SPECIATION AND CELL-SURFACE HYDROPHOBICITY DURING BACTERIAL OXIDATION OF A COMPLEX COPPER CONCENTRATE

A comparison was made of ferrous iron release during the dissolution o f a complex copper concentrate by thermophiles Sulfolobus BC, Acidianu s brierleyi (DSM 1651), Metallosphaera sedula (DSM 5348) and mesophile s Thiobacillus ferrooxidans, DSM 583, ATCC 11820 and an uncharacterise d enrichment culture. The release of Fe2+ coincided with the appearanc e of both elemental sulphur and Cu+, but the concentrations of acid co nsumed and sulphur produced were not stoichiometric relative to copper released. Two of the thermophiles displayed very hydrophilic surface properties and low attachment to the sulphide. These organisms also re leased Fe2+. In Contrast the more hydrophobic thermophile released lit tle Fe2+. The mesophilic cultures displayed intermediate values for su rface hydrophobicity and for both Fe2+ and S-degrees production.