Electrical Stress-Directed Evolution of Biocatalyst Texcoco Soil Community for Microbial Fuel Cell

摘要

Anode-respiring bacteria (ARB) perform an unusual form of respiration in which their electron acceptor is a solid anode. The focus of this study was to characterize the electrical stress direct evolution of biocatalysts as a way of enriching the community with ARB for microbial fuel cell. We gave the electrical stress continually to the Texcoco bacterial community at -150mV/SCE. The 4th day current started to increase and attained the maximum current of 0.35mA in the 15th day. The current in this period was associated to biofilm growth. On the 15th day and by using cyclic voltammetry, an irreversible electron transfer reaction of alkaliphilic cytochrome was found, due to the electrode fouling. From the impedance measurement, the biofilm ARB resistance was determined (～250Ω). Further confocal microscopy studies of biofilm ARB revealed ～6μm thickness. In the single chamber microbial fuel cell, the electrochemical stressed biofilm-ARB exhibited a maximum power density of 79m W/m~2.