A highly efficient O2 cathode based on bilirubin oxidase from Bacillus pumilus operating in serum

Here we report, for the first time, the efficient reduction of O2 in serum using a glassy carbon electrode modified with a new bilirubin oxidase from Bacillus pumilus and a polycationic redox polymer, without coating the electrode with any protective membrane. After 3.3 h of continuous operation in serum, the new cathode only lost 9% of its current density while an electrode made with Trachyderma tsunodae lost more than 38% within the same period of time. This result, in combination with the high thermostability, low sensitivity to chloride anions and high activity, makes the new BOD a promising candidate for the development of cathodes for implanted biofuel cells