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The Douglas fir holocellulose was prepared by Wise’s(8) modification of Jayme's sodium chlorite procedure(9). The hemicelluloses were extracted using 24% potassium hydroxide followed by 17% sodium hydroxide containing 5% boric acid. Meier(31) reported that barium hydroxide can be used to purify polysaccharide mixtures. The mode of action presumably being the formation of an insoluble complex with the cis-hydroxyl groups of the mannose or galactose integers. By using this method of purification Timell(30) isolated a galactoglucomannan from a 24% potassium hydroxide extract of eastern hemlock holocellulose. Following Timell's scheme the attempt to isolate a galactoglucomannan from Douglas fir did not proceed with the facility suggested. Two purifications by Meier's procedure failed to remove the xylose containing polysaccharide. Further batches of freshly prepared holocellulose were extracted and repeated attempts at the isolation and purification of a galactoglucomannan are at present being pursued. The addition of barium hydroxide not only removed the galactoglucomannan fraction but also purified the xylan which remained in solution. Four barium hydroxide treatments followed by two purifications by means of Fehling's solution gave an arabino-4-0-methyl-D-glucuronoxylan freed from galactose. Previous attempts at the purification of this type of polysaccharide from softwoods have failed to remove the galactose residues. A glucomannan fraction was extracted using 17.5% sodium hydroxide containing 5% boric acid. Four fractionations by the barium hydroxide procedure failed to remove the xylose residues. Two further fractionations via the copper complex removed the last traces of xylose but the fraction still contained about 8% galactose. This is not unusual for it has been reported that the majority of gymnosperm glucomannans contain at least 4% galactose. The glucose to mannose ratio is approximately 1:3.5 which is in the order of a true glucomannan. It appears that the possibility should be seriously considered that the galactose residues present in the so called "glucomannans" are actually integral parts of these polysaccharides. Additional experimental data in the near future will undoubtedly serve to solve the problem. / Science, Faculty of / Chemistry, Department of / Graduate

Orientador: Márcia Justino Rossini Mutton / Coorientador: Sarita Cândida Rabelo / Banca: Carlos Eduardo Vaz Rossell / Banca: Maria das Graças de Almeida Felipe / Banca: Sandra Regina Ceccato Antonini / Banca: Eleni Gomes / Resumo: A produção de etanol no Brasil é desenvolvida principalmente através do caldo e melaço de cana-de-açúcar. Considerando-se o aumento da demanda por combustíveis, a biomassa lignocelulósica surge como alternativa pois é o recurso biológico renovável mais abundante da terra. A produção de cana-de-açúcar gera diversos resíduos, como a palhada, deixada no campo após a colheita mecanizada, e o bagaço, que é separado do caldo na operação de moagem dos colmos de cana, e atualmente existem programas de melhoramento genético que visam o desenvolvimento de variedades com altos teores de lignina, para o uso na geração de energia elétrica. Essa biomassa lignocelulósica é composta por cerca de 70% de polímeros de açúcar, materiais que têm grande potencial para a produção de etanol. Este estudo foi realizado objetivando o uso da palhada, bagaço e clones de cana energia, através de pré-tratamento e hidrólise, avaliando seus potenciais para a produção de etanol. Utilizou-se 6 amostras de biomassa: a palhada de três variedades de cana-de-açúcar, coletadas em épocas diferentes; bagaço de cana; e dois clones de cana energia. Estes materiais foram caracterizados com relação a composição de celulose, hemicelulose, lignina, extrativos e cinzas e, logo após, passaram por pré-tratamento ácido, do qual foi obtido um licor, que foi concentrado e destoxificado, para o uso no processo fermentativo. Utilizou-se a estirpe de levedura Rhodotorula glutinis que apresenta habilidade de assim... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Ethanol production in Brazil is mainly developed through sugarcane juice and molasses. Considering the increased demand for fuels, lignocellulosic biomass appears as an alternative because it is the most abundant renewable biological resource on earth. Sugar cane production generates various residues, such as straw, left in the field after mechanized harvesting, and bagasse, which is separated from the broth in the milling operation of sugarcane fields, and there are currently breeding programs that Aim at the development of varieties with high lignin contents, for use in the generation of electric energy. This lignocellulosic biomass is composed of about 70% of sugar polymers, which materials have great potential for the production of ethanol. This study was carried out with the objective of using straw, bagasse and sugar cane clones, through pre-treatment and hydrolysis, evaluating its potential for ethanol production. Six biomass samples were used: the straw of three sugarcane varieties, collected at different times; sugarcane bagasse; And two sugar cane clones. These materials were characterized with respect to the composition of cellulose, hemicellulose, lignin, extractives and ashes and, thereafter, underwent acid pretreatment, from which a liquor was obtained, which was concentrated and detoxified, for use in the fermentation process. The yeast strain Rhodotorula glutinis was used which has the ability to assimilate xylose. Fermentations were performed in three replicates, evaluating the cell viability, viability of shoots and shoots of the cells. The consumption of xylose and ethanol production were also evaluated. The amount of mineral nutrients at all stages of this research was analyzed. The enzymatic hydrolysis of cellulignin was performed and the composition of the hydrolyzate was evaluated. From the dried biomass, analyzes of scanning electron (Complete abstract click electronic access below) / Doutor

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