Sony's biobattery
Sony, of Tokyo, has developed a biobattery designed to generate electricity when glucose dehydrogenase and diaphorase enzymes digest sugar at the anode with the help of vitamin K3 and cofactor NADH. Bilirubin oxidase is used to reduce oxygen at the cathode with the help of potassium ferricyanide. Sony's prototype can power a small 50mW device for about two hours, depending on glucose concentration and enzymatic lifespan, and the battery is expected to be inexpensive because it uses cellophane in the separator. It also will be nontoxic due to the absence of metals and acids. Sony has not revealed its shelf life, but admits the duration of enzymatic activity is highly variable. A company spokesman says new enzymes are being developed to lengthen lifespan, as are new methods for immobilizing enzymes at each polar end. There are not yet biobatteries on the market, but Aichi Prefecture, Japan–based Toyota; Tokyo-based Canon; and Osaka, Japan-based Panasonic also have projects in the works, as do academic labs at Kyoto University, Kumamoto University and Tohoku University. In the US, researchers from St. Louis University in Missouri have developed a fuel cell battery that runs on sugar from soft drinks and tree sap, and the University of Massachusetts is experimenting with a battery based on bacteria isolated from aquifer sediments. Beyond the battery, Sony is exploring other areas of biotech, with nanopore-based biosensors and surgical imaging technologies in the works, and past programs have focused on the development of DNA nanowires. AC
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