Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2018-06-28T22:53:24Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) jessica_pereira_matos.pdf: 1785661 bytes, checksum: f5dbf30e3ce913eae470d1e958272e42 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-07-18T12:52:05Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) jessica_pereira_matos.pdf: 1785661 bytes, checksum: f5dbf30e3ce913eae470d1e958272e42 (MD5) / Made available in DSpace on 2018-07-18T12:52:05Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) jessica_pereira_matos.pdf: 1785661 bytes, checksum: f5dbf30e3ce913eae470d1e958272e42 (MD5) Previous issue date: 2017 / Na produ??o do bioetanol lignocelul?sico, as hexoses provenientes da celulose s?o fermentadas a etanol por muitos micro-organismos que ocorrem naturalmente. Entretanto, as pentoses, provenientes da hidr?lise da hemicelulose, como xilose e arabinose, s?o fermentadas a etanol por poucas esp?cies selvagens conhecidas e com baixos rendimentos. H?, portanto, necessidade de sele??o de estirpes de leveduras que sejam capazes de fermentar pentoses e glicose conjuntamente e de forma eficiente. Neste estudo, duas linhagens de leveduras, Candida akabanensis UFVJM-R131 e Galactomyces geotrichum UFVJM-R10, foram avaliadas na fermenta??o alco?lica da fra??o hemicelul?sica de torta de girassol solubilizada por hidr?lise com ?cido dilu?do. A hidr?lise da hemicelulose foi realizada misturando-se 31% de biomassa seca em solu??o de H2SO4 a 6%, que foi mantida por 38 minutos a temperatura de 121?C a 1 atm. A caracteriza??o cromatogr?fica do hidrolisado obtido revelou a exist?ncia de glicose (7,57 g L-1), xilose (19,53 g L-1) e arabinose (8,85 g L- 1), al?m de 5-hidroximetilfurfural (0,71 g L-1), furfural (0,05 g L-1) e ?cido ac?tico (5,27 g L- 1). Ambas as leveduras mostraram-se capazes de produzir etanol a partir do hidrolisado ?cido da torta de girassol. Os processos conduzidos com as leveduras G. geotrichum UFVJM-R10 e C. akabanensis UFVJM-R131 apresentaram valores de YP/S de 0,29 e 0,27 g etanol g-1 a??cares, respectivamente. As quantidades dos inibidores identificados no hidrolisado n?o afetaram a efici?ncia da fermenta??o alco?lica. A suplementa??o do hidrolisado com fontes de nitrog?nio e minerais aumentou a taxa de consumo da xilose e da arabinose. Os resultados obtidos permitiram concluir que as linhagens G. geotrichum UFVJM-R10 e C. akabanensis UFVJMR131 possuem potencial para a produ??o de bioetanol a partir da fra??o hemicelul?sica de biomassas vegetais. / Disserta??o (Mestrado) ? Programa de P?s-gradua??o em Biocombust?veis, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / In the production of bioethanol lignocellulosic, the hexose from cellulose are fermented to ethanol by many microorganisms that occur naturally. Though, the pentoses from hemicellulose hydrolysis, as xylose and arabinose, are fermented to ethanol by few known wild strains. This fact point the need to select strains of yeasts capable of ferment pentoses and glucose together more efficiently. In the present study, two lineages of yeast, Candida akabanensis UFVJM-R131 and Galactomyces geotrichum UFVJM-R10, were evaluated on alcoholic fermentation of hemicellulosic fraction from sunflower cake solubilized by hydrolysis with dilute acid. The hydrolysis of hemicellulose was performed utilizing 31% of dry biomass in H2SO4 at 6% under 121?C and pressure at 1 atm for 38 minutes. Chromatographic characterization of the hydrolyzate obtained showed the presence of glucose (7.57 g L-1), xylose (19.53 g L-1) and arabinose (8.85 g L-1), besides 5-hydroxymethylfurfural (0.71 g L-1), furfural (0.05 g L-1) and acetic acid (5.27 g L-1). Both yeasts were able to produce ethanol from the acidic hydrolyzate. The fermentation carried out with G. geotrichum UFVJM-R10 and C. akabanensis UFVJM-R131 presented YP/S values of 0.29 and 0.27 g ethanol g-1sugars, respectively. The amounts of the inhibitors identified in the hydrolyzate did not affect the efficiency of the alcoholic fermentation. The supplementation of the hydrolyzate with nitrogen and mineral sources increased the rate of consumption of xylose and arabinose. The results obtained allowed to conclude that the strains G. geotrichum UFVJM-R10 and C. akabanensis UFVJM-R131 have potential for the production of bioethanol from vegetal hemicellulosic fraction.