Abstract:Acidophilic sulfur-oxidizing bacteria (SOB) are the mostly studied bioleaching bacteria which exists widely in the elemental sulfur and sulfides-containing environments. Under impaction by SOB, the solid sulfur and other reduced sulfides (including metal sulfides) are distributed in different chemical speciations inside or outside the cells as well as in the pertinent environmental deposit. The sulfur globules may be stored intra-cellularly after the solid sulfur is activated and transported by the bacteria. The reduced sulfur compounds, with polythiosulfate and/or elemental sulfur as the main transients, are finally oxidized to sulfuric acid. The chemical speciation of elemental sulfur impacted by various SOB was very poorly investigated, further research may provide theoretical support to the elucidation of sulfur metabolism of acidophilic SOB.

Key words: acidophilic sulfur-oxidizing bacteria; chemical speciation; elemental sulfur layer; sulfur globule; sulfur colloid