• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Research on Electron Transfer in the Microenvironment of the Biofilm by Scanning Electrochemical Microscopy

    2019-01-23 08:21:48TIANXiaochunWUXueeZHANDongpingZHAOFengJIANGYanxiaSUNShigang
    物理化學(xué)學(xué)報(bào) 2019年1期

    TIAN Xiaochun , WU Xuee , ZHAN Dongping , ZHAO Feng , JIANG Yanxia , SUN Shigang

    1 College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian Province, P. R. China.

    2 CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, Fujian Province, P. R. China.

    Abstract: Microorganisms exploit extracellular electron transfer (EET) with external minerals during their growth. This process is accompanied by the conversion of chemical energy. Direct electron transfer (DET) from the microorganisms to solid electron acceptors via membrane-bound cytochrome c enzymes or conductive nanowires/pili has been reported. In previous studies, mediated electron transfer (MET) has also been demonstrated to occur through electrochemically active metabolites acting as redox mediators.The microorganisms with EET capabilities have been harnessed for bioelectrochemical systems (BESs) in the bioremediation of environmental contaminants and the production of biofuels and nanomaterials. Electron transfer at the electrode biofilm/solution interface is one of the core phenomena occurring in BESs. The study of the redox reactions occurring in the microenvironment of the biofilm should elucidate the mechanism of microbial EET, which will then help improve the electron transfer efficiency of BESs. The composition of a biofilm is complex and contains many redox secreta and extracellular polymeric substances. Therefore, the specific current generated from the DET or MET pathways cannot be solely detected using classic electrochemical methods. In the present study, the interfacial electron transfer of Shewanella oneidensis MR-1 on an ITO surface was investigated. Cyclic voltammetry (CV) was first applied to study the redox properties of Shewanella and its interaction with ferrocenylmethanol (FcMeOH), which served as an exogenous electron mediator. The cyclic voltammograms showed that the oxidation current of S. oneidensis MR-1 was dramatically enhanced in the presence of 0.01 mmol·L-1 FcMeOH compared to a control, i.e. bacterium-free ITO. This can be explained by the ability of S. oneidensis MR-1 to reduce FcMeOH+ during the positive scan. These results also showed that FcMeOH was a good redox mediator and capable of transferring electrons between the electrode and the bacterial cells. In addition, using the penetration mode in scanning electrochemical microscopy, the current generated from the MET by FcMeOH was collected using a microelectrode. Examination of the approaching curve showed that the current started to increase when the tip was approaching the solution/biofilm interface, providing positive feedback for the FcMeOH-mediated electron transfer between the microelectrode and the bacterial cells. The electrode biofilm/solution microenvironment was also detected, showing the thickness of the solution/biofilm to be 500 μm and the thickness of the biofilm to be 1100 μm. This study indicates that scanning electrochemical microscopy can be used in studying microbial MET. It also provides insight into the electron transfer mechanism of the microbial metabolism from a physical chemistry perspective.

    Key Words: Extracellular electron transfer; Shewanella; Scanning electrochemical microscopy; Penetration mode;Electron shuttle

    云龙县| 边坝县| 普格县| 宜川县| 金阳县| 罗山县| 无极县| 宿松县| 永登县| 岐山县| 当阳市| 疏附县| 湟中县| 青浦区| 织金县| 桓台县| 宣化县| 东方市| 肇州县| 平阳县| 称多县| 河南省| 剑河县| 罗甸县| 兴文县| 邢台县| 浮梁县| 内丘县| 杨浦区| 襄城县| 南宁市| 永德县| 洛川县| 岳普湖县| 微博| 宽甸| 土默特左旗| 阳山县| 和硕县| 新竹市| 视频|