Biotic and abiotic products of Mn(II) oxidation by spores of the marine Bacillus sp. strain SG-1
Biotic and abiotic products of Mn(II) oxidation by spores of the marine Bacillus sp. strain SG-1
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DOI：
10.2138/am.2005.1557
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发表时间：
2005-01-01
影响因子：
3.1
通讯作者：
Villalobos, M
中科院分区：
文献类型：
--
作者：
Bargar, JR;Tebo, BM;Villalobos, M
细菌锰（II）氧化芽孢杆菌属的孢子，菌株SG-1已系统地探讨了在0.22至77天的时间尺度在原位条件下，在不同的Mn（II）浓度。三个互补的技术，K边X射线吸收近边光谱（XANES），X射线发射光谱（XES），和原位同步辐射为基础的X射线衍射（SR-XRD），已被用来检查锰的氧化态，本地的时间依赖性的变化，和远程结构的非晶，结晶，细胞结合，和溶质锰物种。Mn（II）氧化的主要固体生物产物是类似于δ-MnO 2的X射线无定形氧化物，其具有在3.7和4.0之间的Mn氧化态。Mn（II）与原生生物氧化物的反应导致非生物次级产物Feitknechtite或10埃Na phyllomangelite的产生。次级产物的身份取决于Mn（II）浓度，如热力学关系所述。溶解的Mn（II）浓度的减少，其次是矿物学的二次产品的转化。因此，Mn（II）似乎作为还原剂对生物氧化物和控制次级反应产物的稳定性。矿物学的变化类似于这些可能是司空见惯的自然环境中，细菌锰（II）氧化发生，并可能释放吸附的金属离子或改变重要的锰氧化物表面介导的过程，如有机分子的降解率。微生物可能利用这种矿物转化反应来间接控制细胞附近的特定化学条件，这是合理的。
Bacterial Mn(II) oxidization by spores of Bacillus, sp. strain SG-1 has been systematically probed over the time scale 0.22 to 77 days under in-situ conditions and at differing Mn(II) concentrations. Three complementary techniques, K-edge X-ray absorption near-edge spectroscopy (XANES), X-ray emission spectroscopy (XES), and in-situ synchrotron radiation-based X-ray diffraction (SR-XRD), have been utilized to examine time-dependent changes in Mn oxidation state, local-, and long-range structure in amorphous, crystalline, cell-bound, and solute Mn species. The primary solid biogenic product of Mn(II) oxidation is an X-ray amorphous oxide similar to delta-MnO2, which has a Mn oxidation state between 3.7 and 4.0. Reaction of Mn(II) with the primary biogenic oxide results in the production of abiotic secondary products, feitknechtite or a 10 Angstrom Na phyllomanganate. The identity of the secondary product depends upon the Mn(II) concentration as described by thermodynamic relations. A decrease in the dissolved Mn(II) concentration is followed by mineralogic transformation of the secondary products. Thus, Mn(II) appears to act as a reductant toward the biogenic oxide and to control the stability of secondary reaction products. Mineralogic changes similar to these are likely to be commonplace in natural settings where bacterial Mn(II) oxidation is occurring and may liberate sorbed metal ions or alter the rates of important Mn oxide surface-mediated processes such as the degradation of organic molecules. It is plausible that microbes may exploit such mineral transformation reactions to indirectly control specific chemical conditions in the vicinity of the cell.