담수토양에서 메탄생성반응 보효소 니켈의 킬레이팅에 의한 메탄 생산량의 효과적 저감

Abstract

BACKGROUND: Methane(CH4) is considered as thesecondmost potent greenhouse gas after carbon dioxide(CO2). Methanogenesis is an enzyme-mediated multi-stepprocess by methanogens. In the penultimate step,methylated Co-M is reduced by methyl Co-M reductase(MCR) to CH4 involving a nickel-containing cofactor F430. The activity of MCR enzyme is dependent on the F430 andtherefore, the bioavailability of Ni to methanogens isexpected to influence MCR activity and CH4 production insoil. In this study, different doses of EDTA(EthyleneDiamine Tetraacetic Acid) were applied in flooded soils toevaluate their suppression effect on methane production bychelating Ni of methanogenesis cofactor. METHODS AND RESULTS: EDTA was selected aschelating agents and added into wetland and rice paddy soilat the rates of 0, 25, 50, 75, and 100 mmol kg-1 before4-weeks incubation test. During the incubation, cumulativeCH4 production patterns were characterized. At the end ofthe experiment, soil samples were removed from their jarsto analyze total soil Ni and water-soluble Ni content andmethanogen abundance. Methane production from 100mmol application decreased by 55 and 78% in both soilscompared to that from 0 mmol. With increasing applicationrate of EDTA in both soils, water-soluble Ni concentrationsignificantly increased, but total soil Ni and methanogenactivities showed negative relationship during incubationtest. CONCLUSION: The decrease in methane production withEDTA application was caused by chelating Ni of coenzymeF430 and inhibiting methanogenesis by methyl coenzymeM reductase. Consequently, EDTA application decreaseduptake of Ni into methanogen, subsequently inhibited methanogen activities and reduced methane production inflooded soils.