Biomineralization of a poorly crystalline Fe(III)oxide, akaganeite, by an anaerobic Fe(III)-reducing bacterium (Shewanella alga)isolated from marine environment

다국어 초록 (Multilingual Abstract)

Formation of Fe(II)-containing mineral throughmicrobial processes may play an important role in iron and car-bon geochemistry in subsurface environments. Fe(III)-reducingbacteria form Fe(II)-containing minerals such as siderite, magne-tite, vivianite, and green rust using iron oxides. A psychrotolerantFe(III)-reducing bacterium, Shewanella alga (PV-4), was used toexamine the reduction and biomineralization of a poorly crystal-line iron oxide, akaganeite (b-FeOOH), in the absence of a solubleelectron shuttle, anthraquinone disulphonate (AQDS), under dif-ferent atmospheric compositions as well as in HCO3- bufferedmedium (30 to 210 mM). Iron biomineralization was also exam-ined under different growth conditions such as incubation time,electron donors, and electron acceptors. The Fe(III)-reducing bac-terium, PV-4, reduced akaganeite, Fe(III)-citrate, and Co(III)-EDTA using lactate or H2 as an electron donor. The iron biomin-eralization of Fe(III) oxide, akaganeite-as it undergos reductionby an iron reducing bacterium-is a complex process influenced bybiogeochemical factors including microorganisms, bicarbonatebuffer concentration, atmospheric composition, electron donors/acceptors, incubation time, and Eh/pH. From this research wefound that microorganisms do participate in the formation ofdiverse iron minerals and that microbial iron biomineralizationmay affect Fe and C biogeochemistry in subsurface environments.