Carbon steel biocorrosion at 80 °C by a thermophilic sulfate reducing archaeon biofilm provides evidence for its utilization of elemental iron as electron donor through extracellular electron transfer

Mature sulfate reducing archaeon (Archaeoglobus fulgidus) biofilm at 80 degrees C was found more corrosive against C1018 carbon steel under organic carbon starvation. After 3-day pre-growth in enriched artificial seawater medium (EASW), C1018 coupons with biofilms were placed in fresh EASW with reduced carbon source levels for an additional 7 days of incubation. Coupon weight losses were 0.9 mg/cm(2), 2.0 mg/cm(2) and 1.4 mg/cm(2) for this subsequent 7-day starvation period, corresponding to 0%, 90% and 100% carbon source reductions, respectively. Electrochemical tests corroborated the weight loss data, providing evidence for the utilization of elemental iron as electron donor through extracellular electron transfer.