Characterization and stability study of immobilized PQQ-dependent aldose dehydrogenase bioanodes

In this paper, glucose oxidizing bioanodes employing immobilized PQQ‐dependent aldose dehydrogenase were prepared and characterized. The enzyme was immobilized on carbon paper in two different polymeric systems: tetrabutylammonium bromide (TBAB) modified Nafion and butanal modified chitosan. Characterization of the bioanodes included electron microscopy, electrochemical evaluation, as well as stability and leaching studies. Results indicate that the operational degradation was the same but the long term storage stability is better in the case of modified Nafion. The performance of the modified Nafion immobilized bioanodes stayed at 70 % of the initial value after 60 days of storing at 4 °C and 25 °C. Compared to TBAB modified Nafion immobilized bioanodes, butanal modified chitosan immobilized bioanodes showed 50 % activity after eight weeks storage at 4°C and one week storage at 25 °C. However, the electrochemical properties of modified chitosan were better.