Introduction Microbial fuel cells (MFCs) are bioreactors that convert chemical energy stored in the bonds of organic matters into electricity through biocatalysis of microorganisms (Potter, 1911; Cohen, 1931; Davis and Yarbrough, 1962; Moon et al., 2006). The schematic of a typical MFC is shown in Fig. 1. In the sketch below, the anodic and cathodic chamber are separated by a proton exchange membrane (PEM) (Wilkinson, 2000; Gil et al., 2003) that allows transport protons while blocking oxygen...
