The issue with using DNA profiling as a sole method for investigating the role of marine biofilms in corrosion of metallic materials
By Makama, Zakari; Celikkol, Sukriye; Ogawa, Akiko; Gaylarde, Christine; Beech, Iwona
Published in International Biodeterioration & Biodegradation
2018
Abstract
Bacterial community DNA profiles were obtained from surfaces of corroding carbon steel electrodes using next generation sequencing (NGS) Illumina technology. One electrode was exposed to the microbial population present in Key West seawater (KWS), Florida, USA, augmented with Marinobacter J5B1. Another electrode (control) was kept in sterile KWS with the KWS population enclosed within a dialysis tube to prevent biofilm development. Microscopy and culture confirmed sterility of the control electrode, yet DNA was extracted from biofilm-free corrosion deposits. While 16405 Operational Taxonomic Units (OTUs) represented the bioflmed electrode, 64016 OTUs were associated with sterile corrosion deposits. Sequences of Rhodobacteriaceae, a group known to release DNA externally, comprised 50.79% of the latter OTUs. Results demonstrate that in a marine environment corrosion deposits on ferrous alloys can harbour bacterial extracellular DNA (e-DNA). Care must be exercised when using DNA profiling as a sole tool in demonstrating the involvement of biofilms in carbon steel corrosion.