IRON SULFIDE PRODUCTION BY SHEWANELLA STRAIN ISOLATED FROM BLACK POWDER

摘要

Biocorrosion is a serious problem affecting oil and gas industry facilities throughout the world. Traditionally, the sulfate-reducing bacteria group has been considered the foremost responsible for microbially-influenced corrosion (MIC). However, recent studies suggest that other bacteria such as metal-reducing bacteria and methanogens may play a key role in biocorrosion. Shewanella are facultative anaerobic iron-reducing bacteria that are well known for their versatile metabolism. These bacteria have the ability to reduce ferric iron and sulfite, oxidize hydrogen gas, and produce sulfide, and may be involved in biocorrosion. In the present study, the corrosive activity of a strain of Shewanella sp isolated from a gas pipeline (black powder) was investigated. An experiment was conducted to analyze the potential involvement of Shewanella sp in MIC. The corrosion products were characterized by X-ray diffraction identifying iron sulfides, iron oxides, and sulfur. Our results indicate that the strain isolated, S. putrefaciens, plays a key role in corrosion problems in gas pipelines. Further studies related to the interaction between D. desulfuricans and S. putrefaciens, and its implications to biocorrosion are underway, as well as DGGE analysis from several gas pipeline samples.