Estudo da bioeletrocatálise de oxidação de etanol utilizando extrato bruto de sementes de Helianthus annuus como fonte de álcool desidrogenase

• Ano de defesa: 2011
• Autor(a) principal: Silva, Manoel Lucas da
• Orientador(a): Colmati Junior, Flávio
• Banca de defesa: Colmati Junior, Flávio, Yoshioka, Sergio Akinobu, Oliveira, Anselmo Elcana de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Programa de Pós-graduação em Química (IQ)
• Departamento: Instituto de Química - IQ (RG)
• País: Brasil
• Palavras-chave em Português: Biossensor; ADH; Etanol
• Palavras-chave em Inglês: Ethanol
• Área do conhecimento CNPq: QUIMICA ORGANICA::QUIMICA DOS PRODUTOS NATURAIS
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tede/4234

In this work, the enzyme alcohol dehydrogenase (ADH), extracted from sunflower seeds, was used in the preparation of base electrodes of carbon paste. Thus studies have been conducted concerning the electrochemical properties and the catalytic ability of this enzyme for the conversion of ethanol into acetaldehyde, which leads to oxidation of the cofactor β-nicotidamina adenine dinucleotide (NADH). We constructed three working electrodes (A, B and C) for use in the detection of ethanol in phosphate buffer 0.1 mol L-1 (supporting electrolyte) at pH 7.4 and 8.0. Other variables in this study was the mode of extraction of the enzyme using deionized water or 0.1 mol L-1 phosphate buffer (pH 7.4) and form of the enzyme in carbon powder, were used for this mineral oil Nujol ® and Teflon ® solutions and glutaraldehyde. The cyclic voltammetry and chronoamperometry were the two methods used to verify the action of the enzyme in solution. The results showed that the electrodes A and B have inferior performance compared with the electrode C. Finally, electrochemical experiments showed that the enzyme alcohol dehydrogenase derived from crude extract of sunflower seeds has catalytic activity for oxidation of ethanol, but the enzyme does not maintain this constant activity, probably due to the absence of the cofactor which can be in the crude extract in a very low concentration, acting as a limiting reagent in the reaction.