Microbially influenced corrosion in the deep sea: from molecules to mechanisms

Abstract

The understanding of microbial adaptation to high hydrostatic pressure in the context of microbially influenced corrosion remains largely unknown. This leads to challenges in predicting corrosion pressures for metallic structures in the deep sea. In my thesis, by applying diverse approaches and newly developed technologies and techniques, the significance of reproducing realistic culture conditions in order to obtain results which resemble the impact of microbially influenced corrosion in real environment was emphasised. In my study, it was shown that the rates and features of microbial corrosion are strongly affected by the viability and structure of the biofilms as well as by the effect of continuous flow of medium. Additionally, a detrimental impact of high hydrostatic pressure on the corrosion product layer deposited on the metal surface, with the consequential diminishing of its protective potential, was demonstrated. Moreover, increase in hydrostatic pressure led to species-specific proteomic responses, favouring the growth of the piezophilic sulfate-reducing bacterium Pseudodesulfovibrio profundus and enhancing its corrosion capabilities, while, in contrast, inhibiting the metabolism and the corrosiveness of the non piezophilic sulfate-reducing bacterium Desulfovibrio ferrophilus. My thesis also demonstrated how the spatial distribution of metabolites and lipids in corrosive biofilms correlates to anodic and cathodic areas, a correlation that was also reflected in the bacterial phenotype. In summary, my work underscored the importance of improving our understanding of microbially influenced corrosion in deep-sea environments and highlights the potential of innovative approaches in elucidating the mechanisms driving microbial corrosion processes.