Microbiological and chemical corrosion study of Egyptian petroleum samples: microbial community and corrosion activity

Abstract

This research focused on investigating a case of an Egyptian petroleum company, where their fields faced Microbiologically Influenced Corrosion (MIC) problems, relaying of different biological and chemical investigations. Therefore, five samples were collected and used to study their microbial community using 16S rRNA gene amplicon sequencing. The result displayed many potential corrosive bacteria that represented in families, genera and species. The samples were studied concerning total bacterial counts, acid-producing bacteria (APB), slime-forming bacteria (SFB), sulfate-reducing bacteria (SRB). The results displayed that; total bacterial counts were Nil in all samples except one. No samples grew on specific media for APB. All the samples displayed growth results on SFB specific media. Moreover, only one sample has demonstrated a positive result on SRB specific media. One sample was selected to study its corrosion activities; biologically and chemically, upon its diver’s bacterial community, cultivable on microbially specific media and its real-field corrosion severity. The SFB corrosion`s activities were assessed biologically and chemically by determining the variation in bacterial counts, redox potential and metal corrosion rate. Corrosion`s activities of SRB were assessed chemically by examining alterations in dissolved sulfide, redox potential and metal corrosion rate. Surface morphology was examined using scanning electron microscopy. The metal corrosion rates of the uninoculated reactor were 4.025 ± 0.31 and 0.361 ± 0.06 gm2/d under aerobic and anaerobic conditions, respectively. while were 3.21 ± 0.57 and 0.482 ± 0.11 gm2/d for the reactor inoculated with enriched SFB and SRB cultivable bacterial community, respectively.