Biofuel cell based on direct bioelectrocatalysis

A biofuel cell, consisting of two 3mm diameter carbon rod electrodes and operating at ambient temperature in aqueous solution, pH 6, is described. Biofuel cell based on enzymes able to exchange directly electrons with carbon electrodes was constructed and characterized. Anode of the biofuel cell was based on immobilized Quino-hemoprotein alcohol dehydrogenase from Gluconobacter sp. 33 (QH-ADH), cathode on co-immobilized glucose oxidase from Aspergilus niger (GOx)and microperoxidase 8 from the horse heart (MP-8)acting in the consecutive mode. Two enzymes GOx and MP-8 applied in the design of biofuel cell cathode were acting in onsecutive mode and by hydrogen peroxide oxidized MP-8 was directly accepting electrons from carbon rod electrode. If ethanol was applied as an energy source the maximal open circuit potential of the biofuel cell was .125mV. If glucose was applied as energy source the open circuit potential of the cell was +145mV. The maximal open circuit potential (270 mV)was achieved in the presence of extent concentration (over 2 mM)of both substrates (ethanol and glucose). Operational half-life period (ô1/2)of the biofuel cell was found to be 2.5 days.