Biofuel cells with trehalose leading to an insect-implanted power source

This paper reports the first demonstration of a biofuel cell (BFC) using trehalose found in insect hemolymph. The analysis results by liquid chromatography-mass spectrometry (LC-MS) showed that trehalose concentration included in cockroach hemolymph (CHL) was high enough to utilize as a source of power generation. The maximum power density of 6.07 μW/cm² was obtained from CHL with added trehalase (Tre) and mutarotase (Mut). To prevent the open-circuit voltage decrease by adsorption of proteins in the CHL, the electrodes were protected by a dialysis membrane. As a result, the open-circuit voltage was constantly kept around 300 mV for more than 30 min. Furthermore, the maximum power density was increased to 10.5 μW/cm² by using an air diffusion biocathode.