Analysis of the elemental sulfur bio-oxidation by Acidithiobacillus ferrooxidans with sulfur K-edge XANES

Elemental sulfur bio-oxidation by the typical acidophilic sulfur-oxidizing microbe Acidithiobacillus ferrooxidans was investigated by using the technique of sulfur K-edge XANES spectroscopy. Our results showed that the majority of elemental sulfur altered by A . ferrooxidans was dissolved into the organic phase containing carbon disulfide, while a part of it floated. The fitted results of sulfur K-edge XANES spectrum of the floated sulfur showed that the floating part of the elemental sulfur powder was converted to polymeric sulfur and the relative concentration of sulfur in cyclo-octasulfur S 8 and polymeric sulfur was 37.2 and 62.8%, respectively. It seems that the cyclo-octasulfur is converted to the polymeric sulfur and this appears to be necessary for oxidation of elemental sulfur by A . ferrooxidans . The results have important implications for our understanding of the mechanisms for bio-oxidation of elemental sulfur.