Goethite Hinders Azo Dye Bioreduction by Blocking Terminal Reductive Sites on the Outer Membrane of Shewanella decolorationis S12
Goethite Hinders Azo Dye Bioreduction by Blocking Terminal Reductive Sites on the Outer Membrane of Shewanella decolorationis S12
复制标题
针铁矿通过阻断 Shewanella decolorationis S12 外膜上的末端还原位点来阻碍偶氮染料的生物还原
DOI：
10.3389/fmicb.2019.01452
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发表时间：
2019
影响因子：
5.2
通讯作者：
Xu Meiying
中科院分区：
文献类型：
--
作者：
Zhao Gang;Li Enze;Li Jianjun;Liu Feifei;Liu Fei;Xu Meiying
氧化铁是近地表环境中最普遍存在的含Fe（III）矿物，在厌氧条件下可通过参与细菌细胞外电子传递来调控有机污染物的生物转化。到目前为止所描述的机制是基于它们在细菌细胞外呼吸中的氧化还原特性。在这里，我们发现，针铁矿，一个典型的铁（氢）氧化物，抑制生物还原不同的极性偶氮染料的希瓦氏脱色S12不是通过电子竞争，但通过其表面的Fe（III）与细菌外表面的接触。通过衰减全反射（ATR）傅里叶变换红外光谱、二维相关光谱和激光共聚焦显微镜的综合结果，我们发现菌株S12的外膜蛋白MtrC和OmcA是针铁矿表面的关键结合位点。同时，它们也被认为是偶氮染料的重要还原性末端。这些结果表明，针铁矿可能会阻止细菌外膜上的偶氮染料的末端还原位点，以抑制其生物还原。这一发现的针铁矿在生物还原中的作用为含铁（氢）氧化物环境中有机污染物的微生物转化过程提供了新的见解。
Iron (hydr)oxides are the most ubiquitous Fe(III)-containing minerals in the near-surface environments and can regulate organic pollutant biotransformation by participating in bacterial extracellular electron transfer under anaerobic conditions. Mechanisms described so far are based on their redox properties in bacterial extracellular respiration. Here, we find that goethite, a typical iron (hydr)oxide, inhibits the bioreduction of different polar azo dyes by Shewanella decolorationis S12 not through electron competition, but by the contact of its surface Fe(III) with the bacterial outer surface. Through the combined results of attenuated total reflectance (ATR) Fourier transform infrared spectroscopy, two-dimensional correlation spectroscopy, and confocal laser scanning microscope, we found that the outer membrane proteins MtrC and OmcA of strain S12 are key binding sites for goethite surface. Meanwhile, they were identified as the important reductive terminals for azo dyes. These results suggest that goethite may block the terminal reductive sites of azo dyes on the bacterial outer membrane to inhibit their bioreduction. This discovered role of goethite in bioreduction provides new insight into the microbial transformation processes of organic pollutants in iron (hydr)oxide-containing environments.