Microbial corrosion of metals and deterioration of polymeric materials

Microorganisms including bacteria and fungi play an important role in the corrosion of metals and deterioration of polymeric materials Under natural conditions, a thin layer of microorganisms may adhere on surfaces forming the socalled biofilm Microbial colonization on surfaces influences the localized electrochemical characteristics of the metals, resulting in corrosion Other microbial processes inducing corrosion include microbial exopolymeric materials, microbial hydrogen and organic acids produced by the fungi Heterotrophic microorganisms utilize polymers either directly or indirectly as a source of carbon and energy, and the consequences are weakening of the polymer structure Both autotrophic and heterotrophic microorganisms are capable of deteriorating concrete and stone through production of inorganic acids and sulfur transformation respectively Prevention of biodeterioration is largely done by incorporation of biocides, but bacteria develop resistance quickly by mutation after exposure