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Oxidation of elemental sulfur, tetrathionate and ferrous iron by the psychrotolerant Acidithiobacillus strain SS3

Authors :
Kupka, Daniel
Liljeqvist, Maria
Nurmi, Pauliina
Puhakka, Jaakko A.
Tuovinen, Olli H.
Dopson, Mark
Source :
Research in Microbiology. Dec2009, Vol. 160 Issue 10, p767-774. 8p.
Publication Year :
2009

Abstract

Abstract: Mesophilic iron and sulfur-oxidizing acidophiles are readily found in acid mine drainage sites and bioleaching operations, but relatively little is known about their activities at suboptimal temperatures and in cold environments. The purpose of this work was to characterize the oxidation of elemental sulfur (S0), tetrathionate (S4O6 2−) and ferrous iron (Fe2+) by the psychrotolerant Acidithiobacillus strain SS3. The rates of elemental sulfur and tetrathionate oxidation had temperature optima of 20° and 25°C, respectively, determined using a temperature gradient incubator that involved narrow (1.1°C) incremental increases from 5° to 30°C. Activation energies calculated from the Arrhenius plots were 61 and 89kJmol−1 for tetrathionate and 110kJmol−1 for S0 oxidation. The oxidation of elemental sulfur produced sulfuric acid at 5°C and decreased the pH to approximately 1. The low pH inhibited further oxidation of the substrate. In media with both S0 and Fe2+, oxidation of elemental sulfur did not commence until all available ferrous iron was oxidized. These data on sequential oxidation of the two substrates are in keeping with upregulation and downregulation of several proteins previously noted in the literature. Ferric iron was reduced to Fe2+ in parallel with elemental sulfur oxidation, indicating the presence of a sulfur:ferric iron reductase system in this bacterium. [Copyright &y& Elsevier]

Details

Language :
English
ISSN :
09232508
Volume :
160
Issue :
10
Database :
Academic Search Index
Journal :
Research in Microbiology
Publication Type :
Academic Journal
Accession number :
45659302
Full Text :
https://doi.org/10.1016/j.resmic.2009.08.022