elemental iron uptake system, heme peroxidase, converts ferrous iron (Fe(II) to ferric iron (FeIII)) for uptake by [[protein|B31884DC49684A276D65E21A5F59AFDADEB9749C]]-[[protein|3BED98E311EF380AE77327C7F0A83254805089C0]], peroxide detoxification under microaerobic conditions