The role of bacterial communities and carbon dioxide on the corrosion of steel. (September 2015) - Usher, K.M.
Highlights: Two natural bacterial communities grew with only water, CO2 and steel. One of these cultures increased corrosion rates by 45.5% in two months. The species may serve different roles as electron donor or acceptor and fixing CO2 . Organic carbon was not required for growth. CO2 was the final electron acceptor and carbon source. Each species required the others to grow in our culture conditions. Abstract: Natural microbial communities were grown anaerobically with steel as the electron source and CO2 the electron acceptor and carbon source, without organic carbon and typical electron acceptors. The cultures increased corrosion by up to 45.5% compared to sterile controls in two months. Pyrosequencing showed the presence of sulphate reducing bacteria (SRB), sulphur reducing bacteria (S 0 RB) and acetogens likely growing in a syntrophic relationship where SRB extracted electrons from iron, acetogens accepted electrons and reduced CO2 to acetate, which served as carbon source for SRB and/or S 0 RB. The SRB Desulfovibrio mexicanus comprised up to 90.1% of the community.