Nitrite as a causal factor for nitrate ‐dependent anaerobic corrosion of metallic iron induced by Prolixibacter strains

In this study, we isolated fourProlixibacter strains, which belong to the phylumBacteroidetes, and examined their nitrate respiration- and Fe0-corroding activities, together with two previously isolatedProlixibacter strains. Four of the sixProlixibacter strains reduced nitrate under anaerobic conditions, while the other two strains did not. The anaerobic growth of the four nitrate-reducing strains was enhanced by nitrate, which was not observed in the two strains unable to reduce nitrate. When the nitrate-reducing strains were grown anaerobically in the presence of Fe0 or carbon steel, the corrosion of the materials was enhanced by more than 20-fold compared to that in aseptic controls. This enhancement was not observed in cultures of the strains unable to reduce nitrate. The oxidation of Fe0 in the anaerobic cultures of nitrate-reducing strains occurred concomitantly with the formation of nitrite. Since nitrite chemically oxidized Fe0 under anaerobic and aseptic conditions, the corrosion of Fe0- and carbon steel by the nitrate-reducingProlixibacter strains was deduced to be mainly enhanced via the biological reduction of nitrate to nitrite, followed by the chemical oxidation of Fe0 to Fe2+ and Fe3+ coupled to the reduction of nitrite.

Source: MicrobiologyOpen - August 17, 2021 Category: Microbiology Authors: Takao Iino, Nobuaki Shono, Kimio Ito, Ryuhei Nakamura, Kazuo Sueoka, Shigeaki Harayama, Moriya Ohkuma Tags: ORIGINAL ARTICLE Source Type: research