O24-01 : Electrochemical Suppression for Microbially Influenced Corrosion Under an Anaerobic Condition
1Dept. Appl. Chem., Univ. Tokyo, 2Biofunctional Catalyst Research Team, RIKEN CSRS
Much progress has been made for technologies to suppress the rate of iron corrosion in the last century as it costs approximately 4% of GNP per year in USA, except for microbially influenced corrosion (MIC) under an anaerobic condition. As respiratory reactions of sulfate-reducing bacteria (SRB) take a central role for enhancing the rate of the iron corrosion, excess amount of antibiotics are so far used in environment despite its harmfulness and large expense. Here, we show that potential posing on iron surface significantly suppresses the corrosive acitivity of SRB in environmetal microbail flora and isolated cultures. We found by in-vivo electrochemical techniques that corrosion current from microbial consortia with strong corrosive ability decreased more than 90 % after 12 h of preculturing on an iron plate posed at more negative potenital than -0.5 V (vs. standard hydrogen electrode). This effect of the potential posing was also confirmed with two model isolates for studying MIC, Desulfovibrio vulgaris and Desulfovibrio ferrophilus IS5, whose MIC mechanisms are proposed to be distinct. These results suggest that the negative electrode potenital seriously damages SRB attached on the iron substate, indicating this could be a strategy for preventing the MIC caused by SRB with low cost and environmental impact. Possible mechansims will be discussed in detail.