Pigmented Pseudoalteromonas piscicida exhibited dual effects on steel corrosion: Inhibition of uniform corrosion and induction of pitting corrosion

Abstract Employing microorganisms to protect metal surfaces requires significant investigation before they can be translated to field applications. Here, a pigmented Pseudoalteromonas piscicida strain inhibited uniform corrosion but accelerated pitting corrosion of steel materials. The corrosion protection was attributed to a compact biomineralized film composed of calcite and EPSs. However, pitting corrosion still occurred under the film due to pigment secreted by the P. piscicida. This was further corroborated by immersing steel in an abiotic pigment medium. This study introduces a new perspective on the dual roles of bacterial pigments and biomineralization in corrosion.