Utilization of enzyme cascades for complete oxidation of lactate in an enzymatic biofuel cell

Lactate/lactic acid has been considered as a biofuel for enzymatic biofuel cells, but only with single enzyme bioanodes containing lactate dehydrogenase. A single enzyme-based bioanode results in the oxidation of lactate to pyruvate, which only allows for 2 of the total of 12 electrons to be harnessed from the lactate leaving the majority of the energy density of the fuel in the oxidized product (pyruvate); thereby, resulting in low energy density biofuel cells. This paper details an enzyme cascade for complete oxidation of lactate immobilized on a bioanode and employed in a lactate/air biofuel cell. This paper shows that complete oxidation of lactate increases the current density and power density of the biofuel cell, in a similar trend as was observed for complete oxidation of pyruvate in an enzymatic biofuel cell.