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Prolongation of electrode lifetime in biofuel cells by periodic enzyme renewal.
- Source :
-
Applied microbiology and biotechnology [Appl Microbiol Biotechnol] 2012 Nov; Vol. 96 (3), pp. 841-9. Date of Electronic Publication: 2012 Sep 12. - Publication Year :
- 2012
-
Abstract
- Enzymatically catalyzed biofuel cells show unique specificity and promise high power densities, but suffer from a limited lifetime due to enzyme deactivation. In the present work, we demonstrate a novel concept to extend the lifetime of a laccase-catalyzed oxygen reduction cathode in which we decouple the electrode lifetime from the limited enzyme lifetime by a regular resupply of fresh enzymes. Thereto, the adsorption behavior of laccase from Trametes versicolor to buckypaper electrode material, as well as its time-dependent deactivation characteristics, has been investigated. Laccase shows a Langmuir-type adsorption to the carbon nanotube-based buckypaper electrodes, with a mean residence time of 2 days per molecule. In a citrate buffer of pH 5, laccase does not show any deactivation at room temperature for 2 days and exhibits a half-life of 9 days. In a long-term experiment, the laccase electrodes were operated at a constant galvanostatic load. The laccase-containing catholyte was periodically exchanged against a freshly prepared one every second day to provide sufficient active enzymes in the catholyte for the replacement of desorbed inactive enzymes. Compared to a corresponding control experiment without catholyte exchange, this procedure resulted in a 2.5 times longer cathode lifetime of 19 ± 9 days in which the electrode showed a potential above 0.744 V vs. normal hydrogen electrode at 110 μA cm(-2). This clearly indicates the successful exchange of molecules by desorption and re-adsorption and is a first step toward the realization of a self-regenerating enzymatic biofuel cell in which enzyme-producing microorganisms are integrated into the electrode to continuously resupply fresh enzymes.
Details
- Language :
- English
- ISSN :
- 1432-0614
- Volume :
- 96
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Applied microbiology and biotechnology
- Publication Type :
- Academic Journal
- Accession number :
- 22968354
- Full Text :
- https://doi.org/10.1007/s00253-012-4374-8