Fabrication of carbon-felt-based multi-enzyme immobilized anodes to oxidize sucrose for biofuel cells.

A carbon-felt-based multi-enzyme immobilized bioanode for biofuel cells has been successfully developed. The combination of four enzymes, namely, invertase, mutarotase, glucose oxidase, and fructose dehydrogenase, makes it possible to use sucrose--a disaccharide--as fuel for the bioanode. The new electrode exhibits a high oxidation current density of about 12 mA cm(-2) (0.25 V vs. Ag/AgCl) in a McIlvaine buffer solution containing sucrose at pH 6.0 in the half-cell configuration. A sucrose/O(2) biofuel cell composed of the bioanode and an opposite biocathode, including bilirubin oxidase as the enzymatic electrocatalyst, was fabricated, and the new device demonstrated a maximum power density of 2.90 mW cm(-2) with an open-circuit voltage of 0.69 V in the McIlvaine buffer solution. The biofuel cell fabricated using our multi-enzyme anode operates in commercially available beverages that contain only sugar, even without glucose.