A new bacterial isolate from the Black Sea oxidizes sulfide with manganese oxide. Sulfurimonas from Black Sea Sample P14

Sulphide oxidation controls the accumulation of toxic sulphide in aquatic ecosystems and in this context bacterially mediated oxidation of sulphide by oxygen and nitrate are well known processes. Manganese oxide may also be an electron acceptor, however, to date only indirect evidence supports this1, and all attempts to isolate an organism with this metabolism have failed2,3. Here we report the isolation of a bacterial strain from the Black Sea, which belongs to the genus Sulfurimonas and grows autotrophically on sulphide or thiosulphate with manganese oxide as sole electron acceptor. Under our experimental conditions, the rate of the biological reaction is five times faster than strictly chemical process, and sulphide and thiosulphate are oxidized quantitatively to sulphate without accumulation of intermediates. Manganese oxide reduction is accompanied by the formation of reactive dissolved manganese species4,5 and results in precipitation of calcium-rich manganese carbonates, which have both been reported to also accumulate in the open water 6,7 or in sediments8,9. As the genus Sufurimonas is abundant in sulphidic sediments and waters10 and layers of manganese carbonate (rhodochrosite) are frequently found in the geological records9,11, our finding adds important new information on the present and past marine sulphur and manganese cycles.