Introduction
The plant microbial fuel cell (PMFC) is a new technology that can potentially provide renewable and sustainable energy. The PMFC transforms solar energy into electricity through the oxidation of organic compounds originating from photosyn- thesis (De Schamphelaire et al. 2008; Strik et al. 2008). Electricity generation in the PMFC is based on the loss of organic compounds by plant roots (rhizodeposition) (Pinton and Varanini 2007) and oxidation of these organic compounds by electrochemically active bacteria (EAB) (Potter 1911). In the PMFC, electrons, proton and carbon dioxide are produced by oxidation of organic compounds lost by plant roots in the anode.The electrons thatare transferred tothe anode electrode are consumed in the cathode compartment by typically reduc- tion of oxygen to water (Strik et al. 2011).