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Influence of cytochrome charge and potential on the cathodic current of electroactive artificial biofilms
Bioelectrochemistry ( IF 5 ) Pub Date : 2018-07-22 , DOI: 10.1016/j.bioelechem.2018.07.015
Stéphane Pinck , Mengjie Xu , Romain Clement , Elisabeth Lojou , Frédéric P.A. Jorand , Mathieu Etienne

An electroactive artificial biofilm has been optimized for the cathodic reduction of fumarate by Shewanella oneidensis. The system is based on the self-assembly of multi-walled carbon nanotubes with bacterial cells in the presence of a c-type cytochrome. The aggregates are then deposited on an electrode to form the electroactive artificial biofilm. Six c-type cytochromes have been studied, from bovine heart or Desulfuromonas and Desulfuvibrio strains. The isoelectric point of the cytochrome controls the self-assembly process that occurs only with positively-charged cytochromes. The redox potential of the cytochrome is critical for electron transfer reactions with membrane cytochromes of the Mtr pathway. Optimal results have been obtained with c3 from Desulfovibrio vulgaris Hildenborough having an isoelectric point of 10.2 and redox potentials of the four hemes ranging between −290 and −375 mV vs SHE. A current density of 170 μA cm−2 could be achieved in the presence of 50 mM fumarate. The stability of the electrochemical response was evaluated, showing a regular decrease of the current within 13 h, possibly due to the inactivation or leaching of loosely-bound cytochromes from the biofilm.



中文翻译:

细胞色素电荷和电势对电活性人工生物膜阴极电流的影响

一种电活性人工生物膜已被优化,以用于沙氏菌(Shewanella oneidensis)对富马酸的阴极还原。该系统基于多壁碳纳米管与细菌细胞在c型细胞色素存在下的自组装。然后将聚集体沉积在电极上以形成电活性人工生物膜。六个ç型细胞色素进行了研究,从牛的心脏或DesulfuromonasDesulfuvibrio株。细胞色素的等电点控制仅在带正电荷的细胞色素发生的自组装过程。细胞色素的氧化还原电位对于与Mtr途径的膜细胞色素的电子转移反应至关重要。得自Desulfovibrio vulgaris Hildenborough的c 3的等电点为10.2,四个血红素的氧化还原电势相对于SHE的最佳结果已获得最佳结果,其范围为-290至-375 mV。在50 mM富马酸酯的存在下,可以实现170μAcm -2的电流密度。评估了电化学反应的稳定性,显示出在13 h内电流有规律的下降,这可能是由于生物膜中松散结合的细胞色素失活或浸出所致。

更新日期:2018-07-22
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