Involvment of sulfidogenic bacteria in iron corrosion

The involvement of sulfidogenic bacteria in the corrosion of carbon steel i s reviewed. After a brief description of some recent cases drawn from the p etroleum industry, the physiology of the sulfidogenic bacteria which plays the most important role in the mechanism of anaerobic bacterial corrosion i s examined. The involvement of H2S-producing bacteria to the biofilm format ion is a prerequisite for biocorrosion. The hypothetical mechanisms describ ed in the literature are reviewed. Regardless of the physicochemical role p layed by iron sulfides, which have been shown to be non-covering and to hav e good properties of electric conductivity, the acidification arising from cellular metabolism has been found to be an important parameter, not only i n terms of electrochemistry but also in terms of microbial growth. Metaboli c acidification probably explains the ferrous ion supply to the microorgani sm in an environment with a high level of sulfide ions and finally the pers istence of the microbial H2S-producing activity.