Phylogenetic characterization of bacterial consortia obtained of corroding gas pipelines in Mexico

Characterization of the microbial populations formed in gas pipelines is essential to understand the metallic surface-microbe interaction, their role in metal corrosion, and to implement efficient monitoring and control strategies. Microbial community analysis in a corroded gas pipeline in a petroleum-producing facility in the Southeast region in Mexico was performed by traditional cultivation techniques and identification based on 16S rRNA gene sequence. In all samples, thin bacterial biofilms were observed and pitting corrosion was reveled after removing the biofilms. Six pure or mixed cultures of anaerobic bacteria were obtained and their 16S rRNA libraries were constructed, respectively. At least two members of each RFLP profile were sequenced and the phylogenetic affiliations of cloned bacterial 16S rRNA genes indicated that native biofilms were mainly colonized by Desulfovibrio vulgaris and Desulfovibrio desulfuricans, sulfate-reducing bacteria members; Citrobacter freundii, an Enterobacteriaceae member; Clostridium celerecrescens and Clostridium sporogenes, spore-forming anaerobic species and Cetobacterium somerae, a microaerotolerant, non-spore-forming fusobacteria. Some of these species have been observed consistently in other steel pipelines previously, but Cetobacterium members and C. celerecrescens are described for the fist time in this corroded gas pipeline. The potential role of each species in biofilm formation and steel corrosion is discussed.