Akermin, Inc. (St. Louis, MO) inventors Shelley D. Minteer and Robert Arechederra reveal enzymatic bioanodes, biocathodes, and biofuel cells capable of providing transfer of electrons between the fuel fluid and electron conductor in U. S. Patent Application 20090305089. Mitochondria and mitoplasts contain the enzymes and coenzymes of the Kreb's cycle and the electron transport chain, so they are ideally designed for completely oxidizing common fuel fluids, but unlike a microbe, they have fewer transport limitations due to smaller diffusion lengths, no biofilm formation, and no need to transport fuel across the cell wall; these differences lead to higher power densities.
These biofuel cells can be tailored to produce appropriate power for signaling (e.g., radio signal, or a visual or audible alarm) or other applications by altering electrode size, ordering biofuel cells in series or parallel configurations, and altering the fuel concentration. The biofuel cells could also power lights remotely. Biofuel cells may be used in any application that requires an electrical supply, such as electronic devices, commercial toys, internal medical devices, and electrically powered vehicles. Further, the microfluidic biofuel cell may be implanted into a living organism, wherein the fuel fluid is derived from the organism and current is used to power a device implanted in the living organism.
The anode organelle is capable of reacting with a fuel fluid to produce an oxidized form of the fuel fluid, and capable of releasing electrons to the electron conductor. The cathode organelle is capable of reacting with an oxidant to produce water, and capable of gaining electrons from the electron conductor. The organelle immobilization material for both the anode organelle and the cathode organelle is capable of immobilizing the organelle, and is permeable to the fuel fluid and/or the oxidant. The organelle immobilization material is further capable of stabilizing the organelle.
An enzyme or group of enzymes in an organelle catalyzes the oxidation of the fuel fluid at the bioanode. Any organelle that contains enzymes and/or enzymes and electron mediators capable of oxidizing a fuel fluid can be used as the anode organelle. Specifically, glyoxysome, peroxisome, mitochondria, mitoplasts, and combinations thereof can be immobilized and used in the bioanode. In preferred embodiments, the organelle is mitochondria or mitoplasts.
A biofuel cell is an electrochemical device in which energy derived from chemical reactions is converted to electrical energy by means of the catalytic activity of living cells and/or their enzymes. Biofuel cells generally use complex molecules to generate at the anode the hydrogen ions required to reduce oxygen to water, while generating free electrons for use in electrical applications. A bioanode is the electrode of the biofuel cell where electrons are released upon the oxidation of a fuel and a biocathode is the electrode where electrons and protons from the anode are used by the catalyst to reduce oxygen to water. Biofuel cells differ from the traditional fuel cell by the material used to catalyze the electrochemical reaction. Rather than using precious metals as catalysts, biofuel cells rely on biological molecules such as enzymes to carry out the reactions.