Xylans
Mostrando 1-12 de 21 artigos, teses e dissertações.
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1. Endophytic Actinomycetes as Potential Producers of Hemicellulases and Related Enzymes for Plant Biomass Degradation
Abstract Tailor made enzymatic preparation must be design to hydrolyze efficiently plant biomass, once that each plant biomass possesses a distinct cell wall composition. Most of actinomycetes used for plant cell wall degradation are focused on the cellulases and xylanases production. However, a wide range of enzymes must be produced for an efficient degrada
Braz. arch. biol. technol.. Publicado em: 29/08/2019
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2. The distribution of Lignin and Xylan in the Inner and Surface Layers of the Fiber from Eucalyptus Kraft Pulp and its Effects on Oxygen Delignification
The chemical structure and composition of lignin and hemicellulose, as well as the distribution between inner and outer layers of fiber, can adversely affect bleaching operations or fiber-fiber bond on pulp and, consequently the papermaking process. Herein, we have implemented the fractionation and mechanical peeling techniques in order to identify the fines
Mat. Res.. Publicado em: 22/06/2017
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3. INFLUÊNCIA DO CONTEÚDO DE XILANAS NA BRANQUEABILIDADE, PROPRIEDADES HIGROSCÓPICAS, FISICO-MECÂNICAS E ÓPTICA DE POLPAS BRANQUEADAS DE EUCALIPTO
Bleached eucalypt kraft pulps are widely used in print and writing (P&W) and tissue paper manufacture. Among the quality requirements of pulp for these papers, xylan content has been controversial. The objective of this study was to evaluate the influence of xylan content on bleachability, hygroscopic, physic-mechanical and optical properties of the pulp. In
Quím. Nova. Publicado em: 2015-02
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4. Desenvolvimento de propriedades de papéis reciclados por tratamento ultrassônico e adição de xilanas / Development of recycled paper properties by ultrasonic treatment and xylans addiction
This study evaluates the potential of ultrasonic treatment and hemicelluloses addiction to develop mechanical properties of recycled papers. Initially a study was conducted which aimed to determine the better condition to performing the ultrasonic treatment. Were evaluated the effect of pH, pulp consistency and treatment time. Pulp consistency didnt affect t
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 22/07/2010
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5. Influência das xilanas na produção e nas propriedades de polpas de eucalipto para papéis / The influence of xylans on Eucalyptus pulp production and properties for papers
As xilanas desempenham importante função no processo de cozimento e branqueamento de polpas celulósicas e nas propriedades do papel. Modificar os teores dessa hemicelulose permite perder ou ganhar rendimentos de produção e diferenciar as propriedades das polpas e dos papéis produzidos. Os objetivos deste estudo foram produzir polpas marrons e branquead
Publicado em: 2009
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6. Caracterização das O-acetil-(4-O-metilglicurono)xilanas isoladas da madeira de Eucalyptus urograndis
The O-acetyl-4-O-methyl-(glucurono)xylans were isolated from E. urograndis by extraction with dimethyl sulfoxide, analysed for monosaccharide composition and structurally characterized by NMR spectroscopy. These xylans contained one 4-O-methyl-glucuronic acid substituent and 5.5 acetyl groups for approximately 10 xylose residues. About 10% of 4-O-methyl-gluc
Química Nova. Publicado em: 2008
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7. Effect of age of the wood of eucalyptus in its chemical and pulpability, and bleachability and properties of the pulp / Efeito da idade da madeira de eucalipto na sua química e polpabilidade, e branqueabilidade e propriedades físicas da polpa
The concern about the quality of the wood that enters a cellulose factory has been focused on many studies, once the productive process and final product are under great influence of the original raw material. Considering the demand for younger trees, the effect of the age of the wood in the chemical constitution and the variables of the process, as well as
Publicado em: 2008
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8. Obtenção de insumos quimicos a partir do aproveitamento integral do bagaço de cana
Sugar cane bagasse was pre-treated by steam explosion in a 0.65 L stainless-steel reactor. The experiments were carried out at temperatures ranging from 165 to 210°C and for 5 to 60 min, using 11 g of water-free bagasse. At 190°C ca. 36% of the sugar cane bagasse was dissolved after 15 min. Under these conditions, 86% of glucans was recovered in the form o
Publicado em: 1995
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9. Fermentation of xylans by Butyrivibrio fibrisolvens and other ruminal bacteria.
The ability of Butyrivibrio fibrisolvens and other ruminal bacteria (6 species, 18 strains) to ferment a crude xylan from wheat straw or to ferment xylans from larchwood or oat spelts was studied. Liquid cultures were monitored for carbohydrate utilization, cell growth (protein), and fermentation acid production. B. fibrisolvens 49, H17c, AcTF2, and D1 grew
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10. Degradation and utilization by Butyrivibrio fibrisolvens H17c of xylans with different chemical and physical properties.
Hemicelluloses, mainly xylans, can be a major component of diets consumed by ruminants and undergo various degrees of microbial digestion in the rumen. The ability of Butyrivibrio fibrisolvens, a major xylanolytic ruminal species, to degrade and utilize nine chemically and physically different xylans for growth was examined. The arabinoxylans used included t
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11. Purification and Characterization of Aeromonas caviae ME-1 Xylanase V, Which Produces Exclusively Xylobiose from Xylan
A xylanase, which produces exclusively xylobiose from oat spelt and birch xylans, was isolated from the culture medium of Aeromonas caviae ME-1. The enzyme (xylanase V) was purified by ammonium sulfate fractionation, hydrophobic interaction, and ion-exchange and gel filtration chromatographies. The homogeneity of the final preparation was demonstrated by sod
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12. Cell-Wall Polysaccharides of Developing Flax Plants.
Flax (Linum usitatissimum L.) fibers originate from procambial cells of the protophloem and develop in cortical bundles that encircle the vascular cylinder. We determined the polysaccharide composition of the cell walls from various organs of the developing flax plant, from fiber-rich strips peeled from the stem, and from the xylem. Ammonium oxalate-soluble