Levan
Mostrando 13-24 de 75 artigos, teses e dissertações.
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13. ProduÃÃo de oligossacarÃdeos por Zymomonas mobilis
Oligosaccharides are low molecular weight carbohydrates synthesised by living organisms, related with immune defence, viral replication, cell growth, cellcell adhesion and energy storage. Furthermore, they are considered functional foods as a result of their prebiotics properties, which stimulate the intestinal micro flora improving the organic physiology. I
Publicado em: 2003
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14. Estudo comparativo de diferentes metodos e condições da fermentação de melaço de cana-de-açucar por Zymomonas mobilis CP4
This study was carried out to characterize the methods and parameters affecting the fermentation of Zymomonas mobilis CP4 on sugar cane molasses as sustrate. Temperature, pH, Ca++, K+, Mg++ and Cl- were the experimental variables using on a saccharose culture medium. Besides, the effects of clarification and nutrients suplementation of sugar cane molasses wa
Publicado em: 1993
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15. Estudo comparativo da fermentação de glicose e sacarose por Zymomenas mobilis
Z.mobilis NRRL B-806 produced more sucrose hydrolyzing enzyme (S.H.E.) on me di um containing fructose than other tested strains. This extracelular enzyme hydrolysed sucrose and raffinose, but did not hydrolyse melezitose resembling a S-D-fructofuranoside fructohydrolase (E.C. 3.2.1.26). Z.mobilis NRRL B-14022 is able to grow ln a medium containing sucrose a
Publicado em: 1985
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16. Cell-associated levan of Actinomyces viscosus.
Actinomyces viscosus ATCC 15987 was examined for the presence of cell-associated levan by absorption of myeloma proteins with antilevan activity and direct immunofluorescence. Levan was not detectable on the surface of glucose-grown A. viscosus, but after a brief incubation of these cells with 5% sucrose, they were encapsulated with tenaciously adhering leva
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17. Degradation of Levan by Actinomyces viscosus
Actinomyces viscosus ATCC 15987 was examined for its ability to hydrolyze its own levan. Washed whole cells and an ammonium sulfate fraction from cell-free culture fluids were shown to possess levan hydrolase activity. Analyses of reaction mixtures by gel filtration and thin-layer chromatography demonstrated that the product of levan hydrolysis was free fruc
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18. Levan and levansucrase of Actinomyces viscosus.
A levansucrase was demonstrated in the growth medium and in association with the cell surface of Actinomyces viscosus. The amount of enzyme produced relative to cell density is not significantly affected by the growth conditions. Sugar alcohols inhibit growth of the cells. The levansucrase hydrolyzes sucrose to produce free glucose and levan; some free fruct
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19. Fructan from Erwinia herbicola.
Levan production by strains of Erwinia herbicola is common, and this property has some taxonomic significance for species differentiation within the "herbicola" group. The extracellular polysaccharide elaborated by strain 403 was characterized by nuclear magnetic resonance spectroscopy and methylation analysis. Results showed it to be a typical bacterial lev
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20. Influence of Nutritional Factors on the Nature, Yield, and Composition of Exopolysaccharides Produced by Gluconacetobacter xylinus I-2281
The influence of substrate composition on the yield, nature, and composition of exopolysaccharides (EPS) produced by the food-grade strain Gluconacetobacter xylinus I-2281 was investigated during controlled cultivations on mixed substrates containing acetate and either glucose, sucrose, or fructose. Enzymatic activity analysis and acid hydrolysis revealed th
American Society for Microbiology.
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21. Nature of the fructan of Streptococcus mutans OMZ 176.
The fructan of Streptococcus mutans OMZ 176 was shown to have a levan structure by comparing the chromatographic mobilities of the saccharides produced by partial acid hydrolysis of ghe fructan and known levan and inulin. This was confirmed by using concanavalin A as a lectin in a double-diffusion gel technique.
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22. Purification and Characterization of 2,6-β-d-Fructan 6-Levanbiohydrolase from Streptomyces exfoliatus F3-2
Streptomyces exfoliatus F3-2 produced an extracellular enzyme that converted levan, a β-2,6-linked fructan, into levanbiose. The enzyme was purified 50-fold from culture supernatant to give a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weights of this enzyme were 54,000 by SDS-PAGE and 60,000 by gel fil
American Society for Microbiology.
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23. Translucent Colony Form of the Gram-Negative, Levan-Producing Bacterium, Aerobacter levanicum
A spontaneously occurring variation of Aerobacter levanicum, affecting the appearance of colonies on sucrose agar (opaque to translucent colony form), has been observed and studied. This appears to be a mutation that is accompanied by a significant increase in levansucrase (EC 2.4.1.10) activity, in levan production, and by a change in some of the properties
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24. Purification and characterization of an extracellular levansucrase from Pseudomonas syringae pv. phaseolicola.
Levansucrase (EC 2.4.1.10), an exoenzyme of Pseudomonas syringae pv. phaseolicola, was purified to homogeneity from the cell supernatant by chromatography on TMAE-Fraktogel and butyl-Fraktogel. The enzyme has molecular masses of 45 kDa under denaturing conditions and 68 kDa during gel filtration of the native form. In isoelectric focusing, active bands appea