G. fermentans, though it shares similar reduction processes as the other DIRB, displays metabolic characteristics that set it apart from other iron reducers. In the process of respiration, this organism is capable of complete oxidation of the before-mentioned organic acids to CO2 using Fe(III), whereas other iron-reducing species of the families Shewanella or Ferrimonas, for example, oxidize the same organic acids incompletely to acetate. Also in contrast to most other DIRB, G. fermentans cannot utilize elemental sulfur as an electron acceptor, a characteristic it shares with DIRB of the genera Geobacter.
