When many think of biofuels, they probably think about the large scale biofuels that are used to power cars to help make our planet a little more ‘green’. However, many often forget that biofuels may have implications within your own body. For example, it has already been shown in 2007 that Sony has developed a biofuel cell using sugar as the fuel and enzymes as catalysts to power a Walkman. With the demands for reliable power supplies for medical devices for implantable applications, enzymatic biofuel cells has shown particular advantages over conventional energy devices because of the specific activity from enzymes and the capability of miniaturization. As such, a new study published in Energies just a few weeks ago has articulated recently developed technology for the fabrication of enzyme electrodes. They explain that there are essentially two categories that biofuel cells can be classified into. The first is the “product type” in which enzymes generate the fuel substrate for fuel cell by a biocatalytic transformation or metabolic process. The second is direct energy production where enzymes participate in the electron transfer chain between the fuel and the anode. Authors then dive into extensive detail to discuss the two chemical mechanisms by which the enzymes are fabricated: using enzyme electrodes with layered structures or using an enzyme electrode with polymer matrix. Using the latter technique, they have shown that fruit juices (such as orange, grape, and banana juice) can be used as fuels for a membraneless biofuel cell to power many portable electronics; glucose, alcohol, and glycerol have also been used in enzymatic biofuel cells as a substitute for fruit juice. Can you imagine that instead of plugging your ipod in to charge, your pour some fruit juice into it? There is still much work to be done, however. The most significant challenges researchers in this field are facing include: long term stability of the enzyme electrodes, efficient electron transfer between enzymes and electrode surfaces, and improved enzyme biocatalytic activity for biofuel cells with increased power output.
What do Biofuels, Biocells, and Fruit Juice have in Common?