Tuning microbial electrogenic activity by uncouplers

Low energy efficiency, usually limited by insufficient electrogenic activities of anodic bacteria, is currently one of the critical hurdles for application of microbial fuel cells (MFCs) in wastewater treatment. The presence of uncouplers was recently found to ease such a limitation, but the universality of this approach for different uncoupling compounds and bacterial species remain unclear. In this study, the impacts of two uncouplers, 3,3 ',4 ',5-tetrachlorosalicylanilide and 2,4-dinitrophenol, on the electrogenic performances of a number of electrochemically-active bacteria were investigated by WO3 probe and MFC tests. Although the influential degree varied for different uncouplers and bacteria, similar uncoupler impacts were observed: low-concentration promotion and high-concentration inhibition, suggesting that uncoupler regulation on microbial electrogenic activity is a universal phenomenon. This study underscores an untapped important role of uncouplers in regulating microbial electrogenic activities and implies a promising chemical route to strengthen the performance of bioelectrochemical systems. (C) 2015 Elsevier Ltd. All rights reserved.