Applicability of poly-o-aminophenol (POAP) as redox mediator for fungal laccase is investigated and compared with other conducting polymer matrices. Laccase has been entrapped by means of electrochemical polymerization carried out in the solution containing monomer and enzyme. The obtained layers have been characterized by cyclic voltammetry in deaerated and oxygen saturated solutions, as well as by spectroscopic methods. The activity of enzyme has been verified by the standard test using syringaldazine.

Laccase immobilized in POAP matrix catalyses oxygen reduction without any additional mediators. POAP is able to mediate the electron transfer between the enzyme active site and the electrode surface similarly to poly-o-phenylenediamine which has been studied previously [1]. Similar electrocatalytic currents are observed, but the oxygen reduction potential is shifted by as much 0.4 V towards positive direction making POAP the promising candidate for application as material for bio-fuel cell cathodes.

The role of laccase in electrodeposition of POAP has been explored. It was found that the polymer layers obtained during the enzyme entrapment procedure are significantly thicker comparing to POAP layers obtained in absence of enzyme. Furthermore, laccase facilitates formation of longer polymer chains as revealed by UV/VIS absorption spectra. Raman experiments indicate that molecular structures of POAP layers electrodeposited with and without enzyme are similar.

The monomer belongs to typical laccase substrates. Addition of laccase to the o-aminophenol solution causes immediate formation of brownish soluble oligomers. After few hours brown precipitate becomes visible. The precipitate is composed from long polymer chains as revealed by spectroscopic results. POAP formed by laccase contains nanostructures. Its morphology differs from typical polymer samples synthesized chemically or electrochemically. Consequently, application of laccase as polymerization initiator might be manner of controlling the morphology of polymer samples.

[1] B. Palys, A. Bokun, J. Rogalski, Electrochim. Acta 52 (2007) 7075

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/21835 must be provided.

1. Biofuel cell based on carbon nanotubes with covalently bonded laccase and glucose dehydrogenase embedded in cubic phase
2. Biofuel cell based on arylated carbon nanotubes
3. A facile preparation of the nanoparticulate film from conductive and nonconductive particles of the opposite charge
4. Bioelectrocatalytic dioxygen reduction at carbon nanotubes – silicate composite film modified electrode
5. Immobilization of molecules: From self-assembled monolayers to polymeric hollow structures
6. Scanning electrochemical microscopy study of laccase embedded in sol-gel processed silicate film
7. Nanostructured Carbon Electrodes For Oxygen Reduction Catalyzed By Laccase Without any Mediators
8. Optimization of culture medium for laccase production by Trametes versicolor
9. ß-Glucosidases from white rot fungus Phlebia radiata - purification and properties.
10. New methods of immobilization of oxidases at electrodes
11. Designing of cathodes modified with enzymes for the biofuel cell applications
12. Properties of monolayers of azocrown ethers: Ph -tunable equilibria for compounds with substituents containing mobile protons
13. Electrocatalytic reduction of dioxygen by redox mediator and laccase immobilised in silicate thin film