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Development of bioelectrodes for low temperature fuel cell - study of the biocatalysts immobilization and their application in systems with direct electron transfer (DET) and mediated electron transfer (MET)

Grant number: 07/07759-1
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): March 01, 2008
Effective date (End): February 28, 2011
Field of knowledge:Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
Principal Investigator:Ernesto Rafael Gonzalez
Grantee:Camilo Enrique La Rotta Hernández
Home Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
Associated research grant:04/10788-5 - Fundamental and Applied studies of the Eletrocode processes on low temperature fuel cells, AP.TEM

Abstract

This work is directed to the study new ways for enzyme immobilization on the surface of different electrode materials, to be used as bioelectrodes in fuel cells. The chosen biocatalysts correspond to five oxidasic enzymes grouped as: oxidases or group A: Laccase (LAC), Tyrosinase (TYR); peroxidases or group B: chloroperoxidase (CPO) and horseradish peroxidase (HRP); and other oxidases or group C: glucose oxidase (GPO). The methodologies involved during the immobilization of these biocatalysts include: mechanic deposition, gel entrapment and covalent binding to electropolymerized films. Immobilization parameters, as yield and immobilization efficiency, as well as the re-use of the will be evaluated. The soluble and immobilized enzymatic systems will be compared according to their enzymatic properties of: affinity, catalytic efficiency and enzymatic kinetics. Later, the built electrodes will be integrated into mix systems of GPO-PO and GO-OX and evaluated in systems with direct electron transfer (DET) or mediated electron transfer (MET). In the latter case, three different groups of chemical mediators will be used. The first group corresponds to the low toxic synthetic dyes: Thionine, ABTS and Neutral Red; followed by the group of iron coordination compounds: Ferrocene and Ferricyanide. Finally, the last group corresponds to organic radical compounds: HBT and Violuric acid. One or more mediators will be chosen according to their electrochemical properties, solubility, re-cycle rate and chemical mechanism of the recycling. (AU)