Glucose biofuel cell construction based on enzyme, graphite particle and redox mediator compression

We describe herein the fabrication of bioelectrodes by compression of a mixture of graphite particles, enzyme and redox mediator that leads to the immobilization and electrical connection of enzymes. Bioanodes were elaborated by combining graphite with glucose oxidase and ferrocene while biocathodes resulted from the association of graphite, laccase and ABTS. The influence of the enzyme loading on the electrocatalytic properties of bioelectrodes for glucose oxidation and oxygen reduction was examined and an optimum enzyme loading was determined: 5% (w/w). The modulation of the mediator loading led to optimum compositions of 45 and 50% for ABTS and ferrocene, respectively. A biofuel cell configuration was assembled and its performances were investigated as a function of pH providing, at pH 6, a maximum power density and an open circuit voltage of 207 μW cm−2 and 450 mV, respectively.