Stimulation of oxygen to bioanode for energy recovery from recalcitrant organic matter aniline in microbial fuel cells (MFCs) Hao-Yi Cheng a,b,1 , Bin Liang a,1 , Yang Mu c , Min-Hua Cui b , Kun Li b , Wei-Min Wu d , Ai-Jie Wang a,b,* a Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China b State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (SKLUWRE, HIT), Harbin 150090, PR China c CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, PR China d Department of Civil and Environmental Engineering, William & Cloy Codiga Resource Recovery Center, Center for Sustainable Development & Global Competitiveness, Stanford University, Stanford, CA 94305-4020, USA article info Article history: Received 12 December 2014 Received in revised form 5 May 2015 Accepted 6 May 2015 Available online 12 May 2015 Keywords: Microbial fuel cell Oxic bioanode Aniline Oxygen Energy recovery abstract The challenge of energy generation from biodegradation of recalcitrant organics in mi- crobial fuel cells (MFCs) is mainly attributed to their persistence to degradation under anaerobic condition in anode chamber of MFCs. In this work, we demonstrated that electricity generation from aniline, a typical recalcitrant organic matter under anaerobic condition was remarkably facilitated by employing oxygen into bioanode of MFCs. By exposing bioanode to air, electrons of 47.2 ± 6.9 C were recovered with aniline removal efficiency of 91.2 ± 2.2% in 144 h. Limited oxygen supply (the anodic headspace was initially filled with air and then closed) resulted in the decrease of electrons recovery and aniline removal efficiency by 52.5 ± 9.4% and 74.2 ± 2.1%, respectively, and further decline by respective 64.3 ± 4.5% and 82.7 ± 1.0% occurred under anaerobic condition. Community analysis showed that anode biofilm was predominated by several aerobic aniline degrading bacteria (AADB) and anode-respiration bacteria (ARB), which likely cooperated with each other and finally featured the energy recovery from aniline. Cyclic voltammetry indicated that anodic bacteria transferred electrons to anode mainly through electron shuttle. This study provided a new sight to acquaint us with the positive role of oxygen in biodegra- dation of recalcitrant organics on anode as well as electricity generation. © 2015 Elsevier Ltd. All rights reserved. * Corresponding author. Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China. Tel./fax: þ86 10 62915515. E-mail addresses: waj0578@hit.edu.cn, ajwang@rcees.ac.cn (A.-J. Wang). 1 These authors contributed equally to this work. Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/watres water research 81 (2015) 72 e83 http://dx.doi.org/10.1016/j.watres.2015.05.012 0043-1354/© 2015 Elsevier Ltd. All rights reserved.