This work had as its main objective to contribute to the development of a biological detoxification of hemicellulose hydrolysates obtained from different biomass plants using Issatchenkia occidentalis CCTCC M 206097 yeast. Tests with hemicellulosic hydrolysate of sugarcane bagasse in different concentrations were carried out to evaluate the influence of the hydrolysate concentration on the inhibitory compounds removal from the sugarcane bagasse hydrolysate, without reduction of sugar concentration. The highest reduction values of inhibitors concentration and less sugar losses were observed when the fivefold concentrated hydrolysate was treated by the evaluated yeast. In these experiments it was found that the high sugar concentrations favored lower sugar consumption by the yeast. The highest concentration reduction of syringaldehyde (66.67%), ferulic acid (73.33%), furfural (62%), and 5-HMF (85%) was observed when the concentrated hydrolysate was detoxified by using this yeast strain after 24 h of experimentation. The results obtained in this work showed the potential of the yeast Issatchenkia occidentalis CCTCC M 206097 as detoxification agent of hemicellulosic hydrolysate of different biomass plants.

Na primeira etapa deste trabalho avaliou-se o desempenho fermentativo de 6 cepas de leveduras comerciais utilizadas na produção de vinhos e cerveja, em mosto de mel 30°Brix suplementado com 0,5 g/L de peptona e 1 g/L de extrato de levedura. showed that must supplementation with salts or commercial supplement Enovit contributes to the yeast performance. In the next step, it was studied the production of mead on a pilot scale at 18 ° C in polypropylene reactors containing 130 L of wort without supplementation (control), supplemented with Enovit and supplemented with apple pieces (10% m/v). By the end of fermentation, after 60 days, mead was properly characterized physico-chemically regarding the standards of quality and identity for mead, established by Brazilian legislation. The results showed that, with the exception of total acidity, all parameters were in accordance with the standards.After the fermentation, mead was subjected to aging process at 20 ° C by 216 days in oak barrel (50L) plastic gallon (20 L) and glass bottle (20L), and was characterized physico-chemically, as well as regarding the content of total phenolics, antioxidant capacity, presence of bioactive amines and aromatic compounds derived from the oak barrel. The results showed that the mead aged in plastic gallon presented content of "reduced dried extract" below the minimum patterns stated. It was also observed that the use of apples as the must supplement resulted in honey mead with a higher content of phenolic compounds and antioxidant capacity. The concentrations of

Aos meus amigos Juan (irmão paraguaio!) e Boutros, pela receptividade e amizade ao longo desses anos, por todas as conversas, idéias e risadas que demos juntos. Agradeço a vocês toda a ajuda também. Aos meus companheiros de república, Bruno Guedes (obrigado pela amizade e pela trilha sonora do meu mestrado!), Bruno Baratela, Rafael e Fernando.À todos os amigos que encontrei no DEBIQ, Sergião, Victor, Robson, Paulinha, Carol, Juliana, Michel, Germano, Wagner, Guilherme, Dani Cortez, Dani Garcia, Priscila Vaz, João Paulo, Livia, Fernando Budaia, Gina, Claudio, Diana, Maria Fernanda A fermentação de hidrolisados hemicelulósicos tem como principal dificuldade a presença de compostos inibidores ao metabolismo microbiano, derivados da degradação parcial da lignina, degradação dos açúcares e liberação de radicais acetil durante a etapa de hidrólise dos materiais lignocelulósicos. O presente trabalho teve por objetivo avaliar a influência de diferentes tratamentos de destoxificação sobre a composição e fermentabilidade do hidrolisado hemicelulósico de bagaço de cana-de-açúcar na produção de etanol e xilitol. Foram avaliados os seguintes tratamentos: a) alteração de pH com óxido de cálcio e ácido fosfórico seguido de adsorção com carvão ativo; b) utilização de resinas de troca iônica (A-860, A-500PS e C-150 -Amberlite); e c) extração líquido-líquido com interface imobilizada em membrana de fibra oca (Membrana, Charlote, NC -USA), na qual a fase orgânica foi uma mistura de octanol e Alamina 336 e a fase aquosa foi o próprio hidrolisado. De acordo com os resultados, os tratamentos aplicados (a, b e c) promoveram uma redução na concentração de ácido acético de 46,74%, 64,15% e 44,71% e uma redução na absorbância relativa (A.R.) de 82,0%, 94,59% e 46,07%, respectivamente. Na fermentação dos hidrolisados tratados, pela levedura Candida guilliermondii The fermentation of hemicellulosic hydrolysates has as main difficult the presence of compounds derived from partial degradation of lignin, sugars and release of acetyl groups, which are inhibitors of microbial metabolism, during the hydrolysis process of lignocellulosic materials. This study aimed to evaluate the influence of different detoxification treatments on the composition and fermentability of the sugarcane bagasse hemicellulosic hydrolyzate in the production of xylitol and ethanol. The following treatments were evaluated: a) change of pH with calcium oxide and phosphoric acid followed by adsorption with activated charcoal, b) use of ion exchange resins (A-860, A-500 PS and C-150 -Amberlite) and c) liquidliquid extraction with immobilized interface in hollow-fiber membrane (Membrana, Charlote, NC -USA), in which the organic phase was a mixture of octanol and Alamine 336, and the aqueous phase was the hydrolyzate. According to the results, the employed treatments (a, b and c) promoted a reduction of 46.74%, 64.15% and 44.71% in the acetic acid concentration, and a reduction in the relative absorbance (RA) of 82.0%, 94,59% and 46.07% respectively. In the fermentation...