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- Title
Bioelectrocatalytic Activity of Immobilized Alcohol Oxidase on 4-(pyrrole-1-yl) Benzoic Acid Modified Carbon Nanotubes.
- Authors
Kowalewska, Barbara; Jakubow, Katarzyna
- Abstract
A novel bioelectrocatalytic system was prepared by immobilizing alcohol oxidase (AOx) onto multiwalled carbon nanotubes (MWCNT) modified with 4-(pyrrole-1-yl) benzoic acid (PyBA). Functional carboxylic groups from PyBA create covalent amide linkages with amine groups from the enzyme molecule and provide an anchor for the effective immobilization of AOx improving the stability of the whole system. The immobilized enzyme displayed a pair of reversible redox peaks of flavin adenine dinucleotide (FAD) cofactor with the formal potential E 0'=−0.451 V. The response showed a surface-controlled electrode process with the heterogeneous electron transfer rate constant ks=2.7 s−1. Under aerobic conditions AOx(FADH2) can be oxidized to AOx(FAD) by oxygen, which then reacts with ethanol decreasing the cathodic response, which could be used for ethanol detection with a high sensitivity 13.1 μA mM−1 cm−2. The lack of bioactivity towards ethanol in anaerobic conditions suggests the presence of two types of AOx molecules in the system: active with oxygen maintaining the direct electron transfer feature and not active without a redox mediator, due to the deeply embedded FAD cofactor. The polarization curve showed that the electrooxidation current of ethanol appears at −410 mV and reaches 2.0 µA cm−1 at −300 mV. In this case, the bioactivity of AOx to ethanol can be observed offering promising solution for the development of mediatorless systems for application to biosensors and biofuel cells.
- Subjects
ALCOHOL oxidase; CARBON nanotubes; CHARGE exchange; ETHANOL; BIOSENSORS
- Publication
Electroanalysis, 2016, Vol 28, Issue 9, p2050
- ISSN
1040-0397
- Publication type
Article
- DOI
10.1002/elan.201600068