Isolation and identification of bacteria implicated in microbiologically influenced corrosion of mild steel in tap water

When metal constructions are exposed to water, a prevalent issue is Microbiologically Influenced Corrosion (MIC).  This study aims to isolate and identify the bacteria that cause microbiologically influenced corrosion (MIC) of mild steel in tap water over a period of 90 and 180 days, with a particular focus on the bacteria that are engaged in the corrosion process.  At Federal University Oye-Ekiti (FUOYE), Nigeria, mild steel specimens were submerged in tap water from the New Faculty of Science Auditorium (NFSA) to simulate MIC conditions.  Water samples were serially diluted and cultivated on a range of agar media, such as Nutrient and Eosine Methylene Blue, to assess the diversity and load of bacteria, which also accelerated the pace of corrosion. Important bacterial isolates identified by morphological and biochemical examination include species from genera known to accelerate corrosion, such as Escherichia coli, Mycobacterium smegmatis, and S. aureus.  Additionally, the study assessed physicochemical properties like temperature, dissolved oxygen (DO), and pH.  The results showed a consistent rise in corrosion rates when tap water changed, especially in terms of pH and DO levels, which were positively correlated with higher microbial loads and corrosion activity.  The complexity of microbial interactions in MIC is highlighted by the discovery of Mycobacterium smegmatis as a member of the microbial consortium.