Protective Film Formation on Ferrous Metals in Semicontinuous Cultures of Nitrate-Reducing Bacteria

The corrosion of six different carbon–iron alloys has been investigated under anaerobic conditions in semicontinuous cultures of E. coli. Corrosion due directly to bacterial action was significant, but did not correlate with either the amount of nitrate reduced or with the carbon content of the alloys. The corrosion of these alloys was affected by the formation of a film of γ-Fe2O3 which was temporarily protective.