Existence of Hydrogen Sulfide in Iron-salts Grown Thiobacillas ferrooxidans

It was found that iron-salts grown cells of Thiobacillus ferrooxidans, Leptospirillum ferrooxidans, and moderately thermophilic iron-oxidizing bacterial strain TH3 had 2.1-3.7 nmol hydrogen sulfide per mg of cell protein. The hydrogen sulfide in T. ferrooxidans AP19-3 cells was oxidized by hydrogen sulfide: ferric ion oxidoreductase in this bacterium with Fe3+ as an electron acceptor to produce Fe2+. [14C]-C02 was taken into the cells concomitantly with the oxidation of Fe2+ by iron oxidase. Since carbon dioxide fixation is absolutely dependent on energy supplied to the cells, the results suggest that hydrogen sulfide in T. ferrooxidans plays a role as an energy reserve.