Abiotic and Microbial Interactions during Anaerobic Transformations of Fe(II) and [Formula: see text].
Abiotic and Microbial Interactions during Anaerobic Transformations of Fe(II) and [Formula: see text].
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DOI：
10.3389/fmicb.2012.00112
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发表时间：
2012
影响因子：
5.2
通讯作者：
Picardal F
中科院分区：
文献类型：
--
作者：
Picardal F
使用微生物 Fe(II) 氧化作为末端电子受体[硝酸盐依赖性 Fe(II) 氧化，NDFO] 的研究已超过 15 年。尽管有自养分离株和稳定富集的报道，但许多能够进行 NDFO 的细菌都是已知的有机营养还原剂，它们需要有机主要底物（例如乙酸盐）的存在才能实现大量 Fe(II) 氧化。虽然 Fe(II) 氧化与还原反应的热力学是有利的，但除特殊条件外，非生物 Fe(II) 氧化的动力学相对较慢。 NDFO 通常在含有毫摩尔浓度的 Fe(II)、和主要底物的分批培养物中进行研究。在此类系统中，经常观察到 Fe(II) 氧化过程中在培养基中积累。与生物反应和 Fe(II) 的非生物反应相比，反应相对较快。 Fe(II) 氧化的动力学和反应途径受到介质组成和 pH 值、反应物浓度以及 Fe(II) 吸附表面（例如 Fe(III) 羟基氧化物和细胞表面）的存在的强烈影响。在分批培养中，非生物和微生物 Fe(II) 氧化的结合可以改变产物分布，更重要的是，导致细胞内沉淀物和细胞外 Fe(III) 羟基氧化物结壳的形成，这显然限制了进一步的细胞生长和 Fe(II) 氧化。除非采取措施尽量减少或考虑潜在的非生物反应，否则微生物 NDFO 研究的结果可能会因所选实验条件的人为因素、不适当的分析方法的使用以及由此产生的非生物和微生物反应相对重要性的不确定性而变得混乱。在本手稿中，回顾了水性 Fe2+、螯合 Fe(II) 和固相 Fe(II) 的非生物反应以及可能影响微生物系统中总体 NDFO 反应速率的因素。此外，还讨论了使用低底物浓度、连续流系统和实验方案来最大限度地减少实验假象并减少低估或高估微生物 NDFO 率的可能性。
Microbial Fe(II) oxidation using as the terminal electron acceptor [nitrate-dependent Fe(II) oxidation, NDFO] has been studied for over 15 years. Although there are reports of autotrophic isolates and stable enrichments, many of the bacteria capable of NDFO are known organotrophic -reducers that require the presence of an organic, primary substrate, e.g., acetate, for significant amounts of Fe(II) oxidation. Although the thermodynamics of Fe(II) oxidation are favorable when coupled to either or reduction, the kinetics of abiotic Fe(II) oxidation by are relatively slow except under special conditions. NDFO is typically studied in batch cultures containing millimolar concentrations of Fe(II), , and the primary substrate. In such systems, is often observed to accumulate in culture media during Fe(II) oxidation. Compared to abiotic reactions of biogenic and Fe(II) are relatively rapid. The kinetics and reaction pathways of Fe(II) oxidation by are strongly affected by medium composition and pH, reactant concentration, and the presence of Fe(II)-sorptive surfaces, e.g., Fe(III) oxyhydroxides and cellular surfaces. In batch cultures, the combination of abiotic and microbial Fe(II) oxidation can alter product distribution and, more importantly, results in the formation of intracellular precipitates and extracellular Fe(III) oxyhydroxide encrustations that apparently limit further cell growth and Fe(II) oxidation. Unless steps are taken to minimize or account for potential abiotic reactions, results of microbial NDFO studies can be obfuscated by artifacts of the chosen experimental conditions, the use of inappropriate analytical methods, and the resulting uncertainties about the relative importance of abiotic and microbial reactions. In this manuscript, abiotic reactions of and with aqueous Fe2+, chelated Fe(II), and solid-phase Fe(II) are reviewed along with factors that can influence overall NDFO reaction rates in microbial systems. In addition, the use of low substrate concentrations, continuous-flow systems, and experimental protocols that minimize experimental artifacts and reduce the potential for under- or overestimation of microbial NDFO rates are discussed.
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影响因子：
1.5
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HANSEN, HCB
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