Microbial corrosion, also known as microbiologically influenced corrosion (MIC), microbially induced corrosion (MIC) or biocorrosion, occurs when microbes affect the electrochemical environment of the surface on which they are fixed. This usually involves the formation of a biofilm, which can either increase the corrosion of the surface or, in a process called microbial corrosion inhibition, protect the surface from corrosion.
As every surface exposed to the environment is in some way also exposed to microbes,[1] microbial corrosion causes trillions of dollars in damage around the globe annually.[citation needed]
Microbes can locally create hypoxic conditions at the metal surface under a biofilm and contribute to the formation of anodic (oxidation) and cathodic (reduction) sites initiating electrochemical potential differences and electrochemical corrosion. They can also act by either releasing byproducts from their cellular metabolism that corrode metals, or preventing normal corrosion inhibitors from functioning and leaving surfaces open to attack from other environmental factors.[2]