Microbial fuel cells continuously fuelled by untreated fresh algal biomass
X.A. Walter, J. Greenman, B. Taylor, I.A. Ieropoulos
Bristol Robotics Laboratory, Universities of Bristol and of the West of England, T-building, Frenchay Campus, BS16 1QZ, United Kingdom.
Microbial fuel cells (MFCs) are energy transducers that convert organic matter directly into electricity, via the anaerobic respiration of electro-active microorganisms. An avenue of research in this field is to employ algae as the organic carbon fuel source for the MFCs. However, in all studies demonstrating the feasibility of this principle, the algal biomass has always been pre-treated prior to being fed to MFCs, e.g. centrifuged, dried, ground into powder, and/or treated by acid-thermal processes. The alternative presented here, is a flow-through system whereby the MFCs were continuously fed by fresh algal biomass. The system consisted of i) a culture of Synechococcus leopoliensis grown continuously in a photo-chemostat, ii) a pre-digester initiating the digestion of the phototrophs and producing a fuel devoid of oxygen, and iii) a cascade of 9 MFCs, hydraulically and electrically independent. This compartmental system could in theory produce 42 W of electrical power per cubic metre of fresh culture (6 · 105 cells mL-1).
Keywords: Microbial fuel cell; Ceramic membrane; In-line system; Pre-digester; Carbon-neutral energy.