Interspecies interactions of Vibrio azureus and Jeotgalibacillus alkaliphilus on corrosion of duplex stainless steel

Abstract

Investigations of multispecies biofilms and the relationships among these species are crucial for understanding the microbiologically influenced corrosion of metal alloys in actual environments. This study investigated the corrosion of 2205 duplex stainless steel by pure cultures of marine Vibrio azureus and Jeotgalibacillus alkaliphilus and their mixture using different electrochemical and surface analysis techniques. The results showed a significant enhancement of the growth rate and an increase in the biomass population of the biofilm in the presence of both bacteria. Microbial community analysis revealed a harsh competition between the two species. V. azureus benefitted from the competition between the two strains, grew faster, and dominated in the biofilm. Electrochemical results showed an increase in both the anodic dissolution and cathodic oxygen reduction rates of the duplex stainless steel in artificial seawater containing the bacterial mixture. The electrochemical behavior was similar in the presence the bacterial mixture and V. azureus alone, confirming that this bacterium acted as a dominant competitor. AFM images showed larger pits with irregular shapes in the presence of both bacteria, indicating faster pitting propagation.