Corrosive Activity of Microorganisms Isolated from Fouling of Structural Materials in the Coastal Zone of the Barents Sea

Abstract

Potentially corrosive active microorganisms isolated from structural materials with signs of biofouling on the coast of Kislaya Bay (Barents Sea, Russia) were studied: sulfate-reducing, iron-oxidizing and sulfur-oxidizing bacteria. Cultures of sulfate-reducing bacteria (Desulfovibrio sp., Halodesulfovibrio sp.), sulfur-oxidizing bacteria (Dietzia sp.), and iron-oxidizing bacteria (Pseudomonas fluorescens, Bacillus sp.) were identified on the basic of the determining the nucleotide sequences of the 16S rRNA gene. The methods of scanning electron microscopy, energy dispersive microanalysis of the chemical composition and X-ray phase analysis revealed significant changes in the structure and chemical composition of the surface layer of steel reinforcement samples exposed for 28 days in the presence of isolated microorganisms that demonstrated their active participation in corrosion processes. It has been shown that the formation of mineral analogues in corrosion products depends on the strains of studied bacteria and peculiarities of their metabolism. Sulfate-reducing bacteria isolated from the littoral zone of the Barents Sea showed the highest activity in the development of corrosion processes.