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Comparison of Direct and Mediated Electron Transfer for Cellobiose Dehydrogenase from Phanerochaete sordida.

Tasca, Federico LU ; Gorton, Lo LU ; Harreither, Wolfgang; Haltrich, Dietmar; Ludwig, Roland and Nöll, Gilbert (2009) In Analytical Chemistry 81(7). p.2791-2798
Abstract
Direct and mediated electron transfer (DET and MET) between the enzyme and electrodes were compared for cellobiose dehydrogenase (CDH) from the basidiomycete Phanerochaete sordida (PsCDH). For DET, PsCDH was adsorbed at pyrolytic graphite (PG) electrodes while for MET the enzyme was covalently linked to a low potential Os redox polymer. Both types of electrodes were prepared in the presence of single walled carbon nanotubes (SWCNTs). DET requires the oxidation of the heme domain, while MET occurs partially via the heme and the flavin domain at pH 3.5. At pH 6 MET occurs solely via the flavin domain. Most probably, the interaction of the domains decreases from pH 3.5 to 6.0 due to electrostatic repulsion of deprotonated amino acid residues,... (More)
Direct and mediated electron transfer (DET and MET) between the enzyme and electrodes were compared for cellobiose dehydrogenase (CDH) from the basidiomycete Phanerochaete sordida (PsCDH). For DET, PsCDH was adsorbed at pyrolytic graphite (PG) electrodes while for MET the enzyme was covalently linked to a low potential Os redox polymer. Both types of electrodes were prepared in the presence of single walled carbon nanotubes (SWCNTs). DET requires the oxidation of the heme domain, while MET occurs partially via the heme and the flavin domain at pH 3.5. At pH 6 MET occurs solely via the flavin domain. Most probably, the interaction of the domains decreases from pH 3.5 to 6.0 due to electrostatic repulsion of deprotonated amino acid residues, covering the surfaces of both domains. MET starts at a lower potential than DET. The midpoint potentials at pH 3.5 for the flavin (40 mV) and the heme domain (170 mV) were determined with spectroelectrochemistry. The electrochemical and spectroelectrochemical measurements presented in this work are in conformity. The pH dependency of DET and MET was investigated for PsCDH. The optimum was observed between pH 4 and 4.5 pH for DET and in the range of pH 5-6 for MET. The current densities obtained by MET are 1 order of magnitude higher than by DET. During multicycle cyclic voltammetry experiments carried out at different pHs, the PsCDH modified electrode working by MET turned out to be very stable. In order to characterize a PsCDH modified anode working by MET with respect to biofuel cell applications, this electrode was combined with a Pt-black cathode as model for a membraneless biofuel cell. In comparison to DET, a 10 times higher maximum current and maximum power density in a biofuel cell application could be achieved by MET. While CDH modified electrodes working by DET are highly qualified for applications in amperometric biosensors, a much better performance as biofuel cell anodes can be obtained by MET. The use of CDH modified electrodes working by MET for biofuel cell applications results in a less positive onset of the electrocatalytic current (which may lead to an increased cell voltage), higher current and power density, and much better long-term stability over a broad range of pH. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Analytical Chemistry
volume
81
issue
7
pages
2791 - 2798
publisher
The American Chemical Society
external identifiers
  • wos:000264759400050
  • pmid:19256522
  • scopus:64849105998
ISSN
1520-6882
DOI
10.1021/ac900225z
language
English
LU publication?
yes
id
ff7a5326-a9aa-4e0a-9e0b-8bb3263ea2ae (old id 1368055)
date added to LUP
2009-04-07 07:49:37
date last changed
2017-09-24 03:47:13
@article{ff7a5326-a9aa-4e0a-9e0b-8bb3263ea2ae,
  abstract     = {Direct and mediated electron transfer (DET and MET) between the enzyme and electrodes were compared for cellobiose dehydrogenase (CDH) from the basidiomycete Phanerochaete sordida (PsCDH). For DET, PsCDH was adsorbed at pyrolytic graphite (PG) electrodes while for MET the enzyme was covalently linked to a low potential Os redox polymer. Both types of electrodes were prepared in the presence of single walled carbon nanotubes (SWCNTs). DET requires the oxidation of the heme domain, while MET occurs partially via the heme and the flavin domain at pH 3.5. At pH 6 MET occurs solely via the flavin domain. Most probably, the interaction of the domains decreases from pH 3.5 to 6.0 due to electrostatic repulsion of deprotonated amino acid residues, covering the surfaces of both domains. MET starts at a lower potential than DET. The midpoint potentials at pH 3.5 for the flavin (40 mV) and the heme domain (170 mV) were determined with spectroelectrochemistry. The electrochemical and spectroelectrochemical measurements presented in this work are in conformity. The pH dependency of DET and MET was investigated for PsCDH. The optimum was observed between pH 4 and 4.5 pH for DET and in the range of pH 5-6 for MET. The current densities obtained by MET are 1 order of magnitude higher than by DET. During multicycle cyclic voltammetry experiments carried out at different pHs, the PsCDH modified electrode working by MET turned out to be very stable. In order to characterize a PsCDH modified anode working by MET with respect to biofuel cell applications, this electrode was combined with a Pt-black cathode as model for a membraneless biofuel cell. In comparison to DET, a 10 times higher maximum current and maximum power density in a biofuel cell application could be achieved by MET. While CDH modified electrodes working by DET are highly qualified for applications in amperometric biosensors, a much better performance as biofuel cell anodes can be obtained by MET. The use of CDH modified electrodes working by MET for biofuel cell applications results in a less positive onset of the electrocatalytic current (which may lead to an increased cell voltage), higher current and power density, and much better long-term stability over a broad range of pH.},
  author       = {Tasca, Federico and Gorton, Lo and Harreither, Wolfgang and Haltrich, Dietmar and Ludwig, Roland and Nöll, Gilbert},
  issn         = {1520-6882},
  language     = {eng},
  number       = {7},
  pages        = {2791--2798},
  publisher    = {The American Chemical Society},
  series       = {Analytical Chemistry},
  title        = {Comparison of Direct and Mediated Electron Transfer for Cellobiose Dehydrogenase from Phanerochaete sordida.},
  url          = {http://dx.doi.org/10.1021/ac900225z},
  volume       = {81},
  year         = {2009},
}