A Facultative Thermophilic Thiobacillus-like Bacterium: Oxidation of Iron and Pyrite
Year: 1977
Type: conference-paper
Abstract: A rod-shaped microbe, isolated from an Icelandic thermal spring grows well \nat 50° C and oxidises metal sulphides e.g., pyrite (FeS,), pentlandite ((NiFe) SQ) and \nchalcopyrite (CuFeS,). Initial isolation on a modified ferrous iron medium at pH 3.6 \nand 60° C indicated that the bacteria were capable of oxidising ferrous iron but that \ngrowth was poor. For good growth on sulphide minerals, yeast extract is a requirement. \nThis paper reports on the oxidation of soluble ferrous iron and pyrite by this microbe. \nThe microbe grows slowly at 30° C using ferrous iron but does not grow on pyrite; \ngrowth on the latter substrate begins at 40° C. Growth on iron occurs at 50° C, but \nnot at 55° C; growth on pyrite is present at 55° C but not at 60° C. The microbe grows \nusing sulphur as an energy source. The thermophile also grows when yeast extract provides \nthe only apparent energy source. \nPyrite-grown cells were used for manometric experiments. Using ferrous iron, the \noxygen uptake was non-linear, decreasing with time; the rate increased with increasing \npH from 1.3 to 3.2 and also increasing ferrous iron concentration to 8] mM Fe(II). The \nrate then remained the same at 111mM Fe(II). Using pyrite, the oxygen uptake was linear, \nthe rate being a maximum at pH 2.6. Oxidation of pyrite was slight at pH 1.1 and \n3.5. The greatest rate of pyrite oxidation occurred with 100 g c pyrite, the largest \nconcentration tested. Oxygen uptake during the manometric tests with ferrous iron was \nnot greatly affected by the absence of yeast extract; pyrite oxidation was slightly \ngreater without yeast extract. \nThe relevance of the activity of this microbe to biohydrometallurgy is discussed.
Authors: James A. Brierley, N. W. Le Roux
Language: English
Subfield: Metals and Alloys
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3133944238