Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen, Germany.
School of Chemistry, University of Manchester, M13 9PL Manchester, UK. Pacific Northwest National Laboratory, Richland, WA 99352, USA.
Science. 2015 Mar 27;347(6229):1473-6. doi: 10.1126/science.aaa4834.
Microorganisms are a primary control on the redox-induced cycling of iron in the environment. Despite the ability of bacteria to grow using both Fe(II) and Fe(III) bound in solid-phase iron minerals, it is currently unknown whether changing environmental conditions enable the sharing of electrons in mixed-valent iron oxides between bacteria with different metabolisms. We show through magnetic and spectroscopic measurements that the phototrophic Fe(II)-oxidizing bacterium Rhodopseudomonas palustris TIE-1 oxidizes magnetite (Fe3O4) nanoparticles using light energy. This process is reversible in co-cultures by the anaerobic Fe(III)-reducing bacterium Geobacter sulfurreducens. These results demonstrate that Fe ions bound in the highly crystalline mineral magnetite are bioavailable as electron sinks and electron sources under varying environmental conditions, effectively rendering magnetite a naturally occurring battery.
微生物是控制环境中氧化还原诱导的铁循环的主要因素。尽管细菌能够利用固相结合的 Fe(II) 和 Fe(III) 来生长，但目前尚不清楚环境条件的变化是否能够使具有不同代谢途径的细菌在混合价铁氧化物之间共享电子。我们通过磁性和光谱测量表明，光能可以使光养 Fe(II)氧化细菌沼泽红假单胞菌 TIE-1 氧化磁铁矿（Fe3O4）纳米颗粒。在共培养物中，厌氧 Fe(III)还原细菌脱硫杆菌可以使这一过程可逆。这些结果表明，在不同的环境条件下，高度结晶的磁铁矿中结合的 Fe 离子可以作为电子阱和电子源，从而有效地使磁铁矿成为一种天然存在的电池。
