 In 1999, Sorokin et.al isolated and described seven strains of "P. stutzeri" that were able to use nitrite, nitrate, or nitrous oxide as electron acceptors in the oxidation of thiosulfate to tetrathionate under anaerobic conditions.The oxidation of thiosulfate to tetrathionate cannot support autotrophic growth as it only yields one electron, therefore strains that perform this are obligate heterotrophs.Thiosulfate oxidation can occur in the presence or absence of oxygen, although it occurs much slower under anaerobic conditions.