Influence of H2S-producing chemical species in culture medium and energy source starvation on carbon steel corrosion caused by methanogens

Investigations in microbiological-influenced corrosion in recent years have suggested a positive correlation in steel corrosion with methanogens. However, many cases reported in the literature were performed in medium containing Na2S·9H2O or l-cysteine, from which the methanogens can produce H2S that in itself is corrosive. Here it is demonstrated that if all sources of H2S are removed, the methanogenic strain Methanosarcina barkeri only cause accelerated corrosion when deprived of traditional energy sources for methanogenesis, such as methanol and H2. Possible mechanisms for this phenomenon of starvation conditions triggering accelerated corrosion are discussed.