The biofilm characteristics and enhanced performance of a marine microbial-electrolysis-cell-based biosensor under positive anodic potential

正阳极电位下基于海洋微生物电解池的高性能生物传感器及其生物膜特性

Microbial fuel cells have already been used as biosensors to monitor assimilable organic carbon(AOC).However,their signal production from AOC is known to be completely suppressed by dissoved oxygen(DO).In this study,two identical microbial electrolysis cell(MEC)based biosensors were inoculated with marine sediment and operated at two different anodic potentials,namely-300 mV and+250 mV relative to Ag/AgCl.The MEC biosensor operated under positive anodic potential conditions had electrochemically active microbial communities on the anode,including members of the Shewanellaceae,Pseudoalteromonadaceae,and Clostridiaceae families.However,the strictly anaerobic members of the Desulfuromonadaceae,Desulfobulbaceae and Desulfobacteraceae families were found only in the negative anodic potential MEC biosensor.The positive anodic potential MEC biosensor showed several other advantages as well,such as faster start-up,significantly higher maximum current production,fivefold improvement in the AOC detection limit,and tolerance of low dissolved oxygen,compared to those obtained from the negative anodic potential MEC biosensor.The developed positive anodic potential MEC biosensor can thus be used as a real-time and inexpensive detector of AOC concentrations in high saline and low DO seawater.

作为生物传感器,微生物燃料电池已被广泛用于可同化有机碳(AOC)的检测,但溶液中溶解氧(DO)会抑制AOC信号的产生。构建两个相同的基于微生物电解池(MEC)的生物传感器,传感器以海洋沉积物为接种源,并在不同的阳极电位下运行,其阳极电位相对于Ag/AgCl标准电极分别为-300、+250 mV。在+250 mV正阳极电位条件下运行的MEC生物传感器阳极上电活性微生物群落主要包括:Shewanellaceae、Pseudoalteromonadaceae和Clostridiaceae,仅在负阳极电位MEC生物传感器中发现严格厌氧的Desulfuromonadaceae、Desulfobulbaceae和Desulfobacteraceae菌群。与负阳极电位MEC生物传感器相比,正阳极电位MEC生物传感器表现出明显优势,如启动更快、最大电流产量显著提高、AOC检测限提高5倍以及对低溶解氧的高耐受性。提出的实时且经济的正阳极电位MEC生物传感器可以用于高盐度、低DO海水中AOC的检测。