The Mechanism of Fe²⁺ Production by a Moderately Thermophilic Iron-oxidizing Bacterium Strain TI-1

Abstract

The mechanism of Fe²⁺ production by a moderately thermophilic iron-oxidizing bacterium, strain TI-1, was studied. Strain TI-1 produced H₂S outside of the cells when the following five L-amino acids, aspartic acid, glutamic acid, serine, arginine, and histidine, were added to the medium. The activity of H₂S production was completely inhibited by uncouplers and inhibitors of cytochrome c oxidase or sulfite reductase. When Fe³⁺ was added to the H₂S production medium, it was chemically reduced by the H₂S produced by the strain to give Fe²⁺, the sole energy source of this bacterium.