The effect of host media on the development of microbiologically influenced corrosion (MIC)

The objective of this work was to determine the effect of different host media on the initial attachment of Escherichia coli bacteria and subsequent corrosion of 1010 carbon steel coupons. Nutrient broth and minimal media with different carbon sources and phosphate concentrations were used as test solutions in aerobic conditions. The results showed that initial bacterial attachment ( � 60 min) to carbon steel coupons increased with time in all media tested. However, the rate and magnitude of attachment was medium dependent. Both short term (up to 12 h) and relatively longer term (up to 4 weeks) immersion studies showed accelerated corrosion of carbon steel coupons in all minimal media inoculated with E. coli compared to the sterile controls. In contrast, corrosion inhibition was observed in E. coli inoculated nutrient broth medium compared to the sterile controls. These trends were consistent in corresponding cell-free spent media. Mass-loss measurements were also consistent with microscopic observations of the metal surface at different time intervals, indicating that uniform corrosion had occurred. Overall, the results suggest that the host medium play a critical role in the ability of a single type of bacteria to either accelerate or inhibit corrosion of carbon steel.