Influence of a dual-species biofilm on the corrosion of mild steel

The effect of a dual-species biofilm on the corrosion of carbon steel was examined using two bacterial species: the iron-reducer, Shewanella oneidensis (MR-1), and the sulfate-reducer, Desulfovibrio desulfuricans (G20). These experiments exploit the fact that the products of their metabolism (ferrous iron or sulfide) affect the corrosion rate of carbon steel in opposite ways. Electrochemical impedance spectroscopy (EIS) shows that over a short time period, co-cultures of MR-1 and G20 protect steel from corrosion. The fact that an iron-reducing bacterium can inhibit corrosion when a corrosion-enhancing bacterium is present warrants future study with respect to its potential applicability to the design of biological corrosion-control measures.