Functional Insights into Microbial Activity During Steel Corrosion in Freshwater Environments: A Bioinformatic Approach

Abstract

Microbiologically influenced corrosion is known to occur on various materials under diverse environmental conditions. However, information on microbial activity during progression of corrosion in actual environments remains limited. Taxonomic insights into microbial community structures, derived from recent advances in molecular biology techniques, alone are insufficient to understand microbial activity in the corrosion processes. In this study, we aimed to estimate microbial activity during corrosion processes by applying bioinformatic analysis to temporal shifts in microbial community structures observed under actual corrosion conditions. We analyzed the microbial communities present in the corrosion products on various steel materials and in biofilms on non-corroded materials from a freshwater industrial water environment. Abundances of functional genes were estimated from these communities and compared with those estimated from the surrounding water samples. Focusing on energy conversion-related sulfur and nitrogen metabolism, we found substantial shifts in inorganic metabolic gene abundance during the corrosion and biofilm formation processes. Notably, there have been no previous reports addressing metabolic transitions between early and late stages of corrosion. Our findings revealed a notable increase in genes associated with nitrogen fixation and ammonia production during the late corrosion stage, providing crucial insight into nitrogen sources supporting microbial proliferation within corrosion products.