King's College London

Cambridge Life Sciences Plc

Cambridge Life Science Plc

John L Stirling

Jeremy R Mason

Gerard M Delaney

Christopher F Thurston

Hugh P Bennetto

David R DeKeyzer

William H Mullen

Sibel Roller

Donald R White, Jr

Amperometric method for the quantitative determination of

Enzyme electrodes are disclosed which are capable of responding amperometrically to the catalytic activity of the enzyme in the presence of its respective substrate and comprising the enzyme immobilized or adsorbed onto the surface of an electrically conductive support member which consists of or comprises a porous layer of resin-bonded carbon or graphite particles, said particles having intimately mixed therewith, or deposited or adsorbed onto the surface of the individual particles prior to bonding to form said layer, a finely divided platinum group metal, thereby to form a porous, substrate layer onto which said enzyme is adsorbed or immobilized and comprising a substantially heterogeneous layer of resin-bonded carbon or graphite particles, with said platinum group metal dispersed substantially uniformly throughout said layer. The preferred substrate materials are resin bonded platinized carbon paper electrodes comprising platinized carbon powder particles having colloidal platinum adsorbed on the surface of the particles and bonded onto a carbon paper substrate using a synthetic resin, preferably polytetrafluoroethylene, as the binder. The preferred enzyme electrodes are glucose oxidase electrodes comprising glucose oxidase adsorbed or immobilized onto the surface of the substrate.

Immobilized enzyme electrodes

In operation of a microbial fuel cell it has been found that improved efficiency results if the microbes are kept `hungry`, i.e. the cell is run under conditions of fuel supply and load such that electrical output is dependent on fuel concentration, rather than as is conventionally the case being run under excess fuel so that power output is concentration independent. A method and apparatus are described to enable fuel cells to be run under energetic or coulombic efficiency control.

Operation of microbial fuel cells

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London, United Kingdom

John L Stirling