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首页> 外文期刊>Environmental Science & Technology: ES&T >Effects of Humic Substances and Quinones at Low Concentrations on Ferrihydrite Reduction by Geobacter metallireducens
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Effects of Humic Substances and Quinones at Low Concentrations on Ferrihydrite Reduction by Geobacter metallireducens

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摘要

Humic substances (HS) and quinones can accelerate dissimilatory Fe(lll) reduction by electron shuttling between microorganisms and poorly soluble iron(III) (hydr)oxides. The mechanism of electron shuttling for HS is not fully understood, but it is suggested that the most important redox-active components in HS are also quinones. Here we studied the influence of HS and different quinones at low concentrations on ferrihydrite reduction by Geobacter metallireducens. The aquatic HS used were humic and fulvic acids (HA and FA) isolated from groundwater of a deep aquifer in Gorleben (Niedersachsen, Germany). HA stimulated iron reduction stronger than FA down to total HA concentrations as low as 1 mg/L The quinones studied showed large differences: some had strong accelerating effects, whereas others showed only small effects, no effects, or even inhibitory effects on the kinetics of iron reduction. We found that the redox potentials of the most active quinones fall in a narrow range of -137 to -225 mV vs NHE at pH 7. These results give evidence that the kinetic of microbial iron reduction mediated by electron shuttles is mainly controlled by thermodynamic parameters, i.e., by the redox potential of the shuttle compound, rather than by the proportion of dissolved vs adsorbed compound.

著录项

  • 来源
    《Environmental Science & Technology: ES&T》 |2009年第15期|5679-5685|共7页
  • 作者单位

    Institute of Groundwater Ecology, Helmholtz Zentrum Munchen, German Research Center for Environmental Health,Ingolstadter Landstr. I, 65764 Neuherherg, Germany;

    Geomicrobiology Group, Center for Applied Geosciences, Eberhard-Karls-Universitdt Tubingen, 72076 Tubingen, Germany;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 英语
  • 中图分类 环境科学、安全科学;
  • 关键词

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