A biofuel cell based on two immiscible solvents and glucose oxidase and microperoxidase-11 monolayer-functionalized electrodes

Apo-glucose oxidase was reconstituted onto a pyrroloquinoline quinone and flavin adenine dinucleotide phosphate (PQQ-FAD) monolayer associated with a rough Au electrode to yield a bioelectrocatalytically active glucose oxidase, GOx. An electrically contacted PQQ-FAD/GOx monolayer was applied for the biocatalytic oxidation of glucose in an aqueous electrolyte. Microperoxidase-11, MP-11, was assembled as a monolayer on a rough Au electrode and used for the biocatalytic reduction of cumene peroxide in a dichloromethane electrolyte solution. Both biocatalytic electrodes, Au/PQQ- FAD/GOx and Au/MP-11, were integrated into one system, creating a biofuel cell using glucose and cumene peroxide as the fuel substrate and the oxidizer, respectively, in a two-phase liquid system. The biofuel cell generates an open-circuit voltage, V(oc), of ca. 1 V and a short-circuit current density, i(sc), of ca. 830 μA cm^-2. The maximum electrical power, W(max), extracted from the cell is 520 μW at an external optimal load of 0.4 kΩ. The fill factor of the biofuel cell, ∫ = W(max) · I(sc)/^-1 · V(oc)/^-1, is ca. 25%. The biofuel cell based on bioelectrocatalytic processes in two immiscible electrolytes shows a significant increase of the evaluated power in comparison with similar electrocatalytic systems in a single-phase aqueous electrolyte.