A novel membraneless β-glucan/O2 enzymatic fuel cell based on β-glucosidase (RmBgl3B)/pyranose dehydrogenase (AmPDH) co-immobilized onto buckypaper electrode

A novel membraneless beta-glucan/O-2 enzymatic fuel cell was developed by combining a bioanode based on buckypaper modified with co-immobilized Agaricus meleagris pyranose dehydrogenase (AmPDH) and Rhodothermus marinus beta-glucosidase (RmBgl3B) (RmBgl3B-AmPDH/buckypaper) with a biocathode based on solid graphite modified with Myrothecium verrucaria bilirubin oxidase (MvBOx/graphite). AmPDH was connected electrochemically with the buckypaper using an osmium redox polymer in a mediated reaction, whereas MvBOx was connected with graphite in a direct electron transfer reaction. The fuel for the bioanode was produced by enzymatic hydrolysis of beta-glucan by the exoglucanase RmBgl3B into D-glucose, which in turn was enzymatically oxidised by AmPDH to generate a current response. This design allows to obtain an efficient enzymatic fuel cell, where the chemical energy converted into electrical energy is higher than the chemical energy stored in complex carbohydrate based fuel. The maximum power density of the assembled beta-glucan/O-2 biofuel cell reached 26.3 +/- 4.6 mu Wcm 2 at 0.36 V in phosphate buffer containing 0.5 % (w/v) beta-glucan at 40 degrees C with excellent stability retaining 68.6 % of its initial performance after 5 days. The result confirms that beta-glucan can be employed as fuel in an enzymatic biofuel cell.

Automated summary

A novel membraneless enzymatic fuel cell using beta-glucan as fuel was developed. The fuel was produced by enzymatic hydrolysis of beta-glucan, which was then oxidized by specific enzymes to generate a current response. The fuel cell showed high efficiency and excellent stability.