Extracellular electron transfer corrosion mechanism of two marine structural steels caused by nitrate reducing Halomonas titanicae

The extracellular electron transfer (EET) mechanism for corrosion of EH36 steel (with copper) and Q235 steel (without copper) caused by Halomonas titanicae was investigated. Due to copper cytotoxicity, the sessile H. titanicae cells on the EH36 surface was only 18% of that on Q235. This led to its lower EET rate, resulting in EH36 corrosion being 0.67 times of Q235 corrosion. The EET corrosion mechanism was further proven by the increased corrosion of the two steels after injection to the H. titanicae broth of 20 ppm (w/w) (in the broth) riboflavin, an electron mediator known to accelerate EET.