A biofuel cell based on pyrroloquinoline quinone and microperoxidase- 11 monolayer-functionalized electrodes

A pyrroloquinoline quinone (PQQ) monolayer-functionalized-Au-electrode and a microperoxidase-11 (MP-11)-modified Au-electrode are used as catalytic anode and cathode in a biofuel cell element, respectively. The cathodic oxidizer is H₂O₂ whereas the anodic fuel-substrate is 1,4- dihydronicotinamide adenine dinucleotide, NADH. The PQQ-monolayer electrode catalyzes the oxidation of NADH in the presence of Ca²⁺ ions. The MP-1l- functionalized electrode catalyzes the reduction of H₂O₂. The biofuel cell generates an open-circuit voltage, V(OC), of ca. 320 mV and a short-circuit current density, I(SC), of ca. 30 μA · cm^-2. The maximum electrical power, W(max), extracted from the cell is 8 μW at an external load of 3 kΩ. The fill factor of the biofuel cell, f = W(max) · I(SC)^-1 · V(oc)^-1, is ca. 25%.