The Supergen Biological Fuel Cells Consortium is developing advanced technologies that exploit the special properties of biological systems for energy production. A fuel cell produces electricity by reacting a fuel (such as hydrogen or methanol) with oxygen (from air) at a pair of electrodes instead of by combustion,which produces only heat. Normally, fuel cells require expensive components such as special catalysts (platinum) and membranes. In contrast, biological fuel cells use whole organisms or isolated enzymes as catalysts, and a membrane may not be necessary. Two kinds of fuel cell are under development - microbial fuel cells (MFCs) and enzyme-based fuel cells. MFCs have an important role to play in improving our environment and conserving energy whereas enzyme-based fuel cells (EFCs) provide unique opportunities for new kinds of fuel cells, including ones that can be made very small for niche applications such as implantable power sources. MFCs use bacteria, held in contact with an electrode, to convert organic matter (the fuel) into electrical power. They can also be used to remove (oxidising) contaminants from water supplies with the advantage that the electrical power that is simultaneously produced offsets the energy costs for remediation. EFCs exploit the high activities, efficiencies and selectivities of enzymes, recognising that in most cases, and particularly when attached to an electrode, their performance is far superior to man-made catalysts. The Consortium combines expertise in several areas and plans to advance the field on several fronts. These include the following: developing a clear understanding of how microbes colonise electrodes, how useful bacteria can be sustained and undesirable microbes deterred from colonising; understanding and improving the way that electrical charge is transferred between bacteria and electrodes; optimising the design of electrodes from cheap and abundant materials, focusing on such factors as surface chemistry porosity and conductivity; designing novel fuel cells for small-scale special applications; last but not least, finding new ways to replace platinum as the electrocatalyst for oxygen reduction.

Potential Impact:
Biological fuel cells utilise the properties of whole organisms (bacteria) or isolated biomolecules (enzymes) for direct production of electrical energy from the bioelectrochemical reaction of a fuel (substrate, in an anaerobic compartment) with oxygen in air. Microbial fuel cells (MFCs) produce electrical power by harnessing bacterial metabolism. Through developments, MFCs have important potential for electricity production from marginal resources and biological substrates, and for the processing and removal of waste materials from aqueous waste streams. The energy contribution of MFCs therefore derives not only from electricity generation, but also from reduced biomass production (10-50%) and energy savings (MFCs are self-powering) relative to typical waste treatment processes. Scaled-up devices will have considerable potential for (i) generating electrical energy for storage (subject of the Supergen Energy Storage Consortium) for later use at higher power (e.g. in off-grid and remote locations), (ii) self-powering MFCs offering very considerable energy savings for industrial applications such as purification of waste streams (e.g. replacing power-hungry aeration in conventional wastewater treatment), (iii) miniature biological fuel cells offering grid-independent power for sensors and other low power applications. Enzyme-based fuel cells (EFCs) have distinct niche roles, where the emphasis is on small-scale technologies, such as an implantable power source or a self-powered sensor. Enzyme-based cathodes catalyse the oxygen reduction reaction (ORR) and enzyme-based anodes can operate with hydrogen, potentially substituting for platinum at room temperature at both electrodes. Replacement of platinum as electrocatalyst for electrical energy production is a high priority in all fuel cell programmes, because platinum group metals are expensive and their widespread use is increasingly seen as unsustainable due to resource limitation; isolated enzymes (copper oxidases) are highly efficient electrocatalysts for the ORR. Associated with the Consortium is an Industrial Club, which participates in Consortium activities under a multi-way non-disclosure agreement (NDA). Its purpose is to provide an industrial (supplier and end user) perspective on the programme (as a whole and on particular lines of work) and to enable Club organisations to remain up to date with the Consortium and its activities. The new, closely integrated programme aims to promote internationally leading, continuing rapid advance in biological fuel cell technology in the UK, which will not be achieved other than by operating in Consortium mode. The programme necessitates an exceptionally broad base in scientific and engineering backgrounds and in experimental capabilities, as is evident in the academic team assembled. Associated disciplines range from Civil Engineering via Chemical Sciences through to Microbiology, with skills ranging from modelling of microbial community dynamics via electrochemistry to engineering and biotechnological design. The twin priorities of the ongoing consortium will be (i) focussing on power generating devices and (ii) essential developments in the underlying science and engineering that control device performance. The Consortium will seek to provide intensive training opportunities for its own team and other researchers, with a particular focus on UK groups. Annual Workshops on Bioelectrochemical Technology and Devices will be Consortium-led, but not restricted solely to the topic of biological fuel cells. The training impact of the Consortium programme will therefore be extended nationally and internationally.