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Unexpected role of electron-transfer hub in direct degradation of pollutants by exoelectrogenic bacteria |
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| Authors: | Ting-Ting Zhu Zhou-Hua Cheng Sheng-Song Yu Wen-Wei Li Dong-Feng Liu Han-Qing Yu |
| Institution: | 1. CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026 China
Ting-Ting Zhu and Zhou-Hua Cheng contributed equally.;2. School of Life Sciences, University of Science and Technology of China, Hefei, 230026 China Ting-Ting Zhu and Zhou-Hua Cheng contributed equally.;3. CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026 China |
| Abstract: | Exoelectrogenic bacteria (EEB) are capable of anaerobic respiration with diverse extracellular electron acceptors including insoluble minerals, electrodes and flavins, but the detailed electron transfer pathways and reaction mechanisms remain elusive. Here, we discover that CymA, which is usually considered to solely serve as an inner-membrane electron transfer hub in Shewanella oneidensis MR-1 (a model EEB), might also function as a reductase for direct reducing diverse nitroaromatic compounds (e.g. 2,4-dichloronitrobenzene) and azo dyes. Such a process can be accelerated by dosing anthraquinone-2,6-disulfonate. The CymA-based reduction pathways in S. oneidensis MR-1 for different contaminants could be functionally reconstructed and strengthened in Escherichia coli. The direct reduction of lowly polar contaminants by quinol oxidases like CymA homologues might be universal in diverse microbes. This work offers new insights into the pollutant reduction mechanisms of EEB and unveils a new function of CymA to act as a terminal reductase. |
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