Corrosion mechanism of copper in seawater containing the bacterial pyomelanin with redox activity

Copper has bactericidal properties, which can effectively prevent the adhesion of biofilms and thus avoid microbiologically influenced corrosion. In this study, however, pigmented Pseudoalteromonas lipolytica strain producing pyomelanin can accelerate the corrosion of copper even after the bacteria are destroyed by copper ions. Moreover, uniform and pit corrosion were most serious in an abiotic pyomelanin solution. Surface characterization and electrochemical analysis indicated that pyomelanin was the key corrosive factor, owing to its redox cycling properties. The pyomelanin may participate in the oxidation of Cu to Cu (I). This study introduces a new perspective for inhibiting MIC of copper.