硝酸盐依赖性铁（II）氧化过程中的中间过程的识别和定量,Environmental Science & Technology

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硝酸盐依赖性铁（II）氧化过程中的中间过程的识别和定量
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2018-05-03 , DOI: 10.1021/acs.est.8b01122
James Jamieson _{1,

2} , Henning Prommer _{1,

2,

3} , Anna H. Kaksonen _{2,

4} , Jing Sun _{1,

2} , Adam J. Siade _{1,

2,

3} , Anna Yusov ₅ , Benjamin Bostick ₆

Affiliation

对地下环境中微生物驱动的硝酸盐依赖性铁（Fe）氧化（NDFO）进行了深入研究。但是，Fe（II）氧化被生物催化的程度仍不清楚，因为尚未分离出嗜中性铁的氧化和还原硝酸盐的自养生物来确认酶途径的存在。虽然已经分离了营养混合型NDFO细菌，但由于反硝化过程中产生的亚硝酸盐同时发生了非生物氧化，因此使该过程变得更加复杂。在这项研究中，NDFO中生物过程和非生物过程的相对贡献是通过对先前发表的实验数据进行编译和基于模型的解释进行量化的。评估了通过Fe（II）进行化学反硝化（化学反硝化）的动力学，并找到了令人信服的证据，证明有机配体（特别是细菌分泌的外聚合物质）在增强Fe（II）的非生物氧化方面的重要性。但是，仅亚硝酸盐不能解释观察到的Fe（II）氧化程度，总Fe（II）氧化的60–75％归因于所研究菌株的酶促途径：Acidovorax（A。）菌株BoFeN1，2AN，A。淡杆菌TPSY，反硝化副球菌Pd 1222和Pseudogulbenkiania sp。菌株2002。通过严格地量化中间过程，这项研究消除了非生物Fe（II）氧化专门负责NDFO的可能性，并验证了由NDFO细菌催化的其他生物Fe（II）氧化过程的关键作用。

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Identifying and Quantifying the Intermediate Processes during Nitrate-Dependent Iron(II) Oxidation

Microbially driven nitrate-dependent iron (Fe) oxidation (NDFO) in subsurface environments has been intensively studied. However, the extent to which Fe(II) oxidation is biologically catalyzed remains unclear because no neutrophilic iron-oxidizing and nitrate reducing autotroph has been isolated to confirm the existence of an enzymatic pathway. While mixotrophic NDFO bacteria have been isolated, understanding the process is complicated by simultaneous abiotic oxidation due to nitrite produced during denitrification. In this study, the relative contributions of biotic and abiotic processes during NDFO were quantified through the compilation and model-based interpretation of previously published experimental data. The kinetics of chemical denitrification by Fe(II) (chemodenitrification) were assessed, and compelling evidence was found for the importance of organic ligands, specifically exopolymeric substances secreted by bacteria, in enhancing abiotic oxidation of Fe(II). However, nitrite alone could not explain the observed magnitude of Fe(II) oxidation, with 60–75% of overall Fe(II) oxidation attributed to an enzymatic pathway for investigated strains: Acidovorax (A.) strain BoFeN1, 2AN, A. ebreus strain TPSY, Paracoccus denitrificans Pd 1222, and Pseudogulbenkiania sp. strain 2002. By rigorously quantifying the intermediate processes, this study eliminated the potential for abiotic Fe(II) oxidation to be exclusively responsible for NDFO and verified the key contribution from an additional, biological Fe(II) oxidation process catalyzed by NDFO bacteria.

更新日期：2018-05-04

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