Corrosion, Microbial

Abstract

Microorganisms are involved in the corrosion of metals by their active involvement in electrochemical processes, for example, by utilization of hydrogen on metal surfaces. The anaerobic sulfate-reducing bacteria (SRBs) are especially important in the corrosion of a wide range of industrial structures because the sulfur cycle is linked to microbial metabolism, affecting the integrity of metals. Microbial influence corrosion (MIC) can also take place through bacterial exopolysaccharides, by acid production, and by hydrogen metabolism. Recent information indicates that both bacteria and electron shuttling molecules in the environment can also affect the electrochemical processes and therefore the corrosion of metals. Corrosion of metals is an electrochemical process where microorganisms can affect and accelerate the electron consumption from metal surfaces, resulting in dissolution of the metals as ions from matrices. New mechanisms of bacterial involvement have been proposed and tested, but more convincing scientific information is not available as this area of research is multidisciplinary and includes biology and also electrochemistry. Elucidation of the mechanisms also requires the characterization of the specific proteins involved and their function verification. Prevention of MIC mostly includes the use of various biocides and chemicals in industrial applications, and such an approach is problematic as chemicals not only cause environmental problems but also induce resistance in bacteria.