Solar Initiated Biofuel Cell
Natalia Theodora
New Westminster Secondary
Floor Location : S 169 B

Biofuel cell rnThe biofuel cell will be constructed based on Principle of Bioenergetics. The Photosynthesis reaction will take place in the anodic compartment while respiration reaction will occur in the cathodic compartment. Photo-excited electrons from the photosynthesis reaction will be transported by the mediator to the anode and then travels through the external wire to the cathode. The mediator in the cathodic compartment will take up the electrons and transfer it to the electron transfer chain. rnrnEnergy passed from the harvester through neighbouring pigment molecules to the chlorophyll which acts as reaction centre to initiate an Electron Transport system. Electron Transport system consists of two steps; non-cyclic and cyclic electrons flow. Energy absorbs by transport system 2 excites the P680 reaction centre to release electron as well as initiating photolysis process which breaks down water into H+ , free oxygen and electrons. This electrons from the water replaces the excited electrons from the P680 and the excited electrons from the P680 is passed on to the acceptor to the first transport system which is going to go to P700 which is the reaction centre form photo system 1 . The electrons will be passed on to the acceptor afterwards and eventually through the second transport system to NADPH. rnrnThe key to this anodic reaction is to interfere with the transfer of electrons between the P680 to the NADPH. We are going to do this by exerting a mediator with a higher reduction potential then NADPH. The electrons instead of being passed on to NADPH will be taken by the mediator which is a stronger oxidising agent and then taken to the anode to pass through the wire to the cathode. rnrnIn the cathodic compartment, the electrons are taken from the cathode by the mediator and transport it to the Electron Transport Chain inside the E.coli. The mediator acts as a reducing agent in the Electron Transport chain and gives up the electrons. The electrons combine with the H+ from the NADH and FADH2 and free O to produce water. On overall the biofuel cell works based on the cycle of water regeneration process. rnrnThe electrodes used for the biofuel cell is specially made using Carbon Nanotubes as the base and Polypyrrole as a coating. It posses several advantages compare to regular carbon sheet electrodes. Some of them are its non porous property which prevents adsorption of reactants and products ,pseudo-capacitance property and electro-catalytic property. rn