The effectiveness of cathodic protection (CP) on microbiologically influenced corrosion (MIC) control

Cathodic protection (CP) is an electrochemical method, to manage corrosion in different industries, especially in buried and sub-merged environments. In those environments microorganisms are present and can cause microbiologically influenced corrosion (MIC). Most of the industry standards recommend
performing CP using -800 mV (Ag/AgCl), however, if MIC-microorganisms are present, for instance sulfate reducing bacteria (SRB), it is recommended to use even more negative potentials. It is assumed that this will provide adequate protection of the metal. There currently is no information or valid data in
context of CP, on the level of MIC threat and the extent to which more negative potentials can be used to provide adequate protection and not over-protection (due to hydrogen embrittlement threat). Conflicting statements can be found in the literature regarding the effectiveness of CP on MIC, from
reducing biofilm attachment to increasing bacterial activity and biofilm attachment. Recently, the development and lower price of molecular microbiological methods (MMM) have opened the door for more effective studies of the MIC mechanism along with other electrochemical methods and surface
analysis. In this work, the genetic functionality of biofilms formed in the laboratory under CP conditions is investigated using transcriptomics. Gene expression of SRB biofilms under different CP potentials (-800, -850 and -900 mV) will be studied; comparison with control will allow us to distinguish the specific genes that are differentially expressed, leading to a better understanding of the mechanism of CP to affect bacterial activity and diversity.