Polarographic Evidence of the Production of Polythionates During the Bacterial Oxidation of Thiosulphate

Abstract

SUMMARYA polarographic technique and Starkey's alkali method have been applied to the qualitative analysis of thiosulphate, trithionate and pentatliionate and to the quantitative analysis of tetrathionate in filtrates of bacterial cultures grown in an inorganic medium containing sodium thiosulphate. Five strains of autotrophic thiobacilli and one strain of a heterotrophic bacterium produced polythionates. During thiosulphate oxidation by two autotrophic strains which resembled Thiobacillus thiopaws, tetrathionate, small amounts of trithionate, pentathionate and abundant elemental sulphur were produced and the pH fell from c. 7.0 to c. 3-0. I n cultures of one of the three autotrophic strains which resembled T. thiocyanoxidans, about half as much tetrathionate, with even smaller amounts of trithionate and pentathionate, was found; abundant sulphur was precipitated and the pH fell to c. 4.0. I n cultures of the two other strains iesembling T. thiocyanozidans, small amounts of tetrathionate were detected only occasionally ; trithionate and pentathionate were not found, sulphur was deposited and the pH fell to c. 4.5. Much tetrathionate, as well as trithionate and pentathionate, were all readily identified in cultures of the heterotrophic organism; the pH rose to c. 8.7 and no sulphur was formed.

The role of Thiobacillus ferrooxidans in hydrometallurgical processes

“…In this reaction 8 electrons are removed from the substrate and will be carried out through a series of intermediate products: Reactions 1-4 are catalyzed by the sulfur-oxidizing enzyme [89,83,90,91] where sulfite is the product of the reaction. Sulfite is oxidized to sulfate [85] by sulfite-oxidase (reaction 5) with the formation of ATP [88].…”

The Taxonomy of certain Thiobacilli

“…Some authors considered the genus to be a spectrum of types (Baalsrud, 1954), whilst others recognized distinct species, but these varied according to the author (Vishniac & Santer, 1957;Parker & Prisk, 1953). The latest comprehensive study of this group was made in 1953, and in this instance only the utilization of sulphur compounds was investigated and not all the species were examined.…”

Aerobic biodegradation potential of photoprocessing wastewaters

“…However, aerobic conversion of thiosulfate to polythionates (especially tetrathionate, S 4 0 6 2~) has been previously observed (Pankhurst, 1964;and Lu and Kelly, 1988). It has since been discovered that tetrathionate and thiosulfate are both detected by polarography but no clear distinction between the two compounds could be made (both species had the same peak potential) when the previously described polarographic method was used for thiosulfate quantification.…”

“…It has since been discovered that tetrathionate and thiosulfate are both detected by polarography but no clear distinction between the two compounds could be made (both species had the same peak potential) when the previously described polarographic method was used for thiosulfate quantification. By changing supporting electrolytes, it may be possible to separate thiosulfate and tetrathionate and allow their detection polarographically (Pankhurst, 1964). The incomplete oxidation of thiosulfate to sulfate could have been the result of either the lack of readily degradable organic compounds after about nine hours of incubation or more likely due to the formation of polythionates.…”