Microbiologically influenced corrosion of 304L stainless steel caused by an alga associated bacterium Halomonas titanicae

Algae are reported to be corrosive, while little is known about the role of the algae associated bacteria in the corrosion process. In the present study, Halomonas titanicae was isolated from a culture of an alga strain, Spirulina platensis, and identified through 16 S rRNA gene analysis. Corrosion behavior of 304L stainless steel(SS) coupons in the presence and absence of H. titanicae was characterized by using electrochemical measurements and surface analysis. The results showed that H. titanicae significantly accelerated the corrosion rate and decreased the pitting potential of 304L SS in the biotic medium.After removal of the corrosion products and biofilms, severe pitting corrosion caused by H. titanicae was observed. The largest pit depth after 14 d reached 6.6 μm, which was 5.5 times higher than that of the sterile control(1.2 μm). This is the first report revealing that an alga associated bacterium can induce microbiologically influenced corrosion(MIC), and a further concern is raised that whether algae play a role in the MIC process.