A review of cellulosic microbial fuel cells: Performance and challenges

Cellulosic biomass, in the form of lignocellulosic materials, is a renewable and readily accessible source of organic substrate for microbial fuel cells (MFCs). The performances of cellulosic MFCs were compared on a common basis and with respect to the properties of the different cellulosic substrate each utilized. Moreover, the different experimental design approaches employed to overcome performance limitations of cellulosic MFCs were evaluated. Comparison of the mean peak currents and mean peak power densities revealed that MFCs run on cellulose were electrically outperformed by those run on starch but not those run on chitin. It was further observed that coulombic efficiency, the measure of effective substrate utilization for current generation, was greatest for soluble polysaccharide substrates, whether starch or cellulose. For insoluble polysaccharide substrates, coulombic efficiency decreased as the degree of polymerization increased. These and other conclusions indicate that both substrate accessibility and effective substrate utilization are important factors for electrical performance of cellulosic MFCs. The evaluation exposes the need for more thorough and systematic design and analysis of MFC experiments employing cellulose and other polysaccharides as substrates.