2021 Fiscal Year Final Research Report

Analysis of sulfate reducing bacteria capable of electrical microbiologically influenced corrosion

Research Project

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Project/Area Number	19K05807
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 38020:Applied microbiology-related
Research Institution	Central Research Institute of Electric Power Industry
Principal Investigator	Shin-ichi Hirano 一般財団法人電力中央研究所, サステナブルシステム研究本部, 上席研究員 (20392748)
Project Period (FY)	2019-04-01 – 2022-03-31
Keywords	微生物腐食 / 微生物電気腐食 / 硫酸還元菌 / 細胞外電子移動
Outline of Final Research Achievements	Corrosion caused by microorganisms that extract electrons from solid metals (EMIC) has been suggested to play a major role in serious corrosion damage to metal equipment under anaerobic environments. Although understanding of the EMIC mechanism is required for protecting equipment against EMIC, it has not been clarified. In this study, to elucidate the mechanism, three different sulfate-reducing bacteria with EMIC ability were analyzed in the view of the corrosion rate, electrochemical properties, and genes responsible for the reaction of extracting electrons from solid iron. We revealed the three strains have different corrosion rates and a relationship between corrosion rate and electrochemical characteristics of the strains. The strain, which showed the highest EMIC activity among the three strains, was shown to promote corrosion by acting as a cathode on the surface of solid iron, and the presence of membrane proteins involved in extracting electrons from solid iron was estimated.
Free Research Field	微生物電気化学
Academic Significance and Societal Importance of the Research Achievements	既報のEMIC能を有する硫酸還元菌単離株は2株のみであり知見は限定されていた。本研究では独自に取得したEMIC能を持つ3種類の硫酸還元菌について、腐食速度・形態、腐食生成物、電気化学的特性、EMIC反応を担う遺伝子の解析という多面的なアプローチで比較解析を行うことで、新たな腐食形態の発見、腐食速度と電気化学的特性の相関の明確化、固体鉄からの電子引き抜きに関与する遺伝子候補といったEMICのメカニズムに関する新しい知見を得た。本研究の成果は、EMICのメカニズムに学術的に新しい知見を与えるとともに、社会インフラ (金属配管等) におけるEMIC対策技術やリスク診断技術の開発に繋がる知見と言える。