Carbon tetrachloride transformation in a model iron-reducing culture: relative kinetics of biotic and abiotic reactions.
Carbon tetrachloride transformation in a model iron-reducing culture: relative kinetics of biotic and abiotic reactions.
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DOI：
10.1021/es010923
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发表时间：
2002-01
影响因子：
11.4
通讯作者：
M. McCormick;E. Bouwer;P. Adriaens
中科院分区：
文献类型：
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作者：
M. McCormick;E. Bouwer;P. Adriaens
在以水合氧化铁（HFO）为电子受体、乙酸盐为底物、Geelium metallireducens为代表的异化铁还原菌（DIRB）的铁还原模型系统中，研究了生物（细胞介导）和非生物（矿物介导）反应对四氯化碳（CT）转化的贡献.在2-3周的时间内，纳米级磁铁矿颗粒，Fe 3 O 4，始终形成为铁呼吸在这个系统中的产品。在G.金属还原剂或从用过的培养物中回收的洗涤过的磁铁矿颗粒的悬浮液中。蛋白质和表面积归一化的表达式分别来自生物和非生物反应速率。使用模型系统中生长过程中形成的总蛋白质产量和磁铁矿表面积作为比较基础，估计在整个孵育期间，矿物质介导的（非生物）反应比生物反应快60-260倍。我们的结论是G.金属还原菌在该系统中主要通过形成反应性矿物表面而不是通过共代谢机制诱导CT转化。研究结果表明，反应性生物矿物质可以发挥显着的作用，在铁还原环境中的氯化溶剂的自然衰减。一种新的方法，刺激还原转化的污染物可能是促进反应性生物矿物的形成原位。
Contributions of biotic (cell-mediated) and abiotic (mineral-mediated) reactions to carbon tetrachloride (CT) transformation were studied in a model iron-reducing system that used hydrous ferric oxide (HFO) as the electron acceptor, acetate as the substrate, and Geobacter metallireducens as a representative dissimilative iron-reducing bacteria (DIRB). Over a period of 2-3 weeks, nanoscale magnetite particles, Fe3O4, were consistently formed as a product of iron respiration in this system. CT transformation rates were measured independently in resting cell suspensions of G. metallireducens or in suspensions of washed magnetite particles recovered from spent cultures. Protein and surface area-normalized expressions were derived for the biotic and abiotic reaction rates, respectively. Using the yield of total protein and magnetite surface area formed during growth in the model system as a basis for comparison, the mineral-mediated (abiotic) reaction was estimated to be 60-260-fold faster than the biotic reaction throughout the incubation period. We conclude that G. metallireducens induces CT transformation in this system primarily through the formation of reactive mineral surfaces rather than via co-metabolic mechanisms. The findings indicate that reactive biogenic minerals could play a significant role in the natural attenuation of chlorinated solvents in iron-reducing environments. A novel approach for stimulating reductive transformation of contaminants may be to enhance the formation of reactive biogenic minerals in situ.