Biocorrosion control: Current strategies and promising alternatives

Abstract

Metal corrosion is an electrochemical reaction between the environment and a metal, in which microbes are thought to play a very important role. The rates at which various types of metals corrode are dependent upon environmental conditions as well as on the type of metals. The most well studied bacteria involved in biocorrosion are the anaerobic sulphate reducing bacteria (SRB) and other bacteria such as methanogens, acid producers as well as the aerobic iron respirers and manganese oxidisers. The biofilm produced by the microorganisms facilitates bicorrosion by altering the chemistry such as pH, pressure, oxygen levels and nutrients at the interface between the metal and the bulk solution. Therefore biofilms can be used to alter the conditions at a metal surface, and to accelerate or inhibit corrosion. In this review, the proposed mechanisms of how bacteria contribute to the biocorrosion processes and the groups of bacteria involved will be included. Different strategies for biocorrosion control will also be discussed. Biological control strategies such as biocompetitve exclusion and the use of antimicrobial producing biofilm forming bacteria show increasing promise as more effective, environmental friendly and long term method of corrosion controls. Key words: Microbially influenced corrosion, biocorrosion control strategies, biofilms, microorganisms, biocompetitive exclusion.