Comparison of chitosan and nafion-chitosan coated bioelectrodes in enzymatic glncose biofnel cells

Abstract

Here we evaluated the performance of enzymatic glucose biofuel cells. The significance of bioelectrodes employed in biofuel cell design is highly dependent on the effective immobilization of enzyme to enable the enzyme to present an orientation that is favorable for direct electron transfer (DET) from the active center of the enzyme to the final current collector. We examined chitosan and nafion-chitosan based coatings on immobilized pyrroloquinoline quinone dependent glucose dehydrogenase (PQQ-GDH) and bilirubin oxidase (BOD) as anodic and cathodic enzymes, respectively. The enzymes were immobilized on multi-walled carbon nanotubes (MWCNTs). The performance of the assembled biofuel cells exhibited interesting operational stability. Operating under DET, the biofuel cell with bioelectrodes coated with chitosan produced the highest power (156 μW) output. PQQ-GDH bioanodes with various enzyme concentrations were evaluated to access their performance and stability. The bioanode with 2.5 mg/ml immobilized PQQ-GDH demonstrated long term stability and generated a maximum power density of 1.6 mW/cm2 in the fuel cell assembly when compared to higher enzyme load concentration (≥ 5 mg/ml PQQ-GDH).