Seleção de leveduras fermentadoras de xilose e análise do exometaboloma de Meyerozyma guilliermondii UFV-1

• Ano de defesa: 2014
• Autor(a) principal: Silveira, Fernando Augusto da
• Orientador(a): Silveira, Wendel Batista da
• Banca de defesa: Rodrigues, Fábio de Avila , Nascimento, Antonio Galvão do
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Microbiologia Agrícola
• Departamento: Associações micorrízicas; Bactérias láticas e probióticos; Biologia molecular de fungos de interesse
• País: BR
• Palavras-chave em Português: Leveduras; Fermentação; Cândida guilliermondii; Meyerozyma guilliermondii; Biocombustível; Xilitol
• Palavras-chave em Inglês: Yeast; Fermentation; Candida guilliermondii; Meyerozyma guilliermondii; Biofuel; Xylitol
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::MICROBIOLOGIA AGRICOLA
• Link de acesso: http://locus.ufv.br/handle/123456789/5375

There is a great interest in the selection of yeasts able to convert xylose, the main pentose released from the pretreatment of lignocellulosic biomass, into metabolites of industrial interest, such as fuel, food ingredients, drugs and antimicrobial drugs. Therefore, five xylose fermenting yeasts were selected from the culture collection of the Laboratory of Physiology of Microorganisms, Department of Microbiology, Universidade Federal de Viçosa. Among them, Meyerozyma guilliermondii UFV-1 was able to completely consume xylose available in the medium and convert it into ethanol and other metabolites of industrial relevance. Its fermentation potential was evaluated at different oxygen concentrations. Ethanol production was higher in hypoxia where the concentration of dissolved oxygen (DO) in the culture medium was 10% (1.98 g L -1). The higher production of xylitol, 5.34 g L-1, was also obtained in hypoxia. The effect of ethanol and acetic acid, furfural and hydroxymethyl furfural, inhibitors generated during the acid pre-treatment, on the growth of M. guilliermondii UFV-1 was evaluated. The yeast was able to grow in ethanol concentration of 13.5 g L-1 corresponding to the maximum amount that can be produced from the xylose released from hemicellulose. Furthermore, M. guilliermondii UFV-1 grew in concentrations of acetic acid, furfural and hydroxymethyl furfural which are normally found in hemicellulose hydrolysates. Analysis of M. guilliermondii UFV-1 exometaboloma revealed no difference in the metabolites profile produced in the two growth conditions evaluated: low specific growth rate and near maximum specific growth rate. Five metabolites of biotechnological interest were identified: valeric, caproic and butyric acids, used as antifungal; glicofuranoside used by the pharmaceutical industry in the control of diabetes; and malic acid, compound used in food industry as acidulant and flavor enhancer. Therefore, the identification of these extracellular metabolites demonstrates the biotechnology potential of this yeast not only to produce ethanol and xylitol, but other chemicals of industrial interest.