Exopolymers
Mostrando 1-12 de 16 artigos, teses e dissertações.
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1. Mecanismos de remoção de compostos orgânicos no sistema de lodos ativados de uma fábrica de polpa Kraft branqueada de eucalipto / Removal mechanisms of organic compounds in a eucalyptus bleached kraft pulp mill activated sludge plant
The composition and adsorptive capacity of extracellular polymeric substances (EPS) in a eucalyptus bleached kraft pulp mill activated sludge plant were investigated. Samples of primary and secondary effluents and activated sludge were collected over five months. Effluents were characterized by quantifying dissolved organic carbon (DOC), chemical (COD) and b
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 25/02/2011
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2. Enzymatic and biodegrader activities of petroleum microorganisms from Campos Basin (Pampo Sul) / Atividades enzimaticas e de biodegração de microorganismos do petroleo da Bacia de Campos (Pampo Sul)
Amostras de águas de formação de petróleo e óleos foram coletadas na Formação Pampo, situada na Bacia de Campos, através das quais, aplicando-se diferentes condições de cultivo, foram recuperadas 92 linhagens de bactérias aeróbias. Dentre os isolados, obtidos, 29 foram identificados por técnicas moleculares baseadas em DNAr 16S, observando-se a
Publicado em: 2006
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3. Direct Incorporation of Glucosamine and N-Acetylglucosamine into Exopolymers by Gluconacetobacter xylinus (=Acetobacter xylinum) ATCC 10245: Production of Chitosan-Cellulose and Chitin-Cellulose Exopolymers
Gluconacetobacter xylinus (=Acetobacter xylinum) ATCC 10245 incorporated 2-amino-2-deoxy-d-glucose (glucosamine) and 2-acetamido-2-deoxy-d-glucose (N-acetylglucosamine), but not 3-O-methyl-d-glucose or 2-deoxy-d-glucose into exopolymers. Incorporation was confirmed by gas chromatography with and without mass spectrometry, Fourier transform infrared, and 1H n
American Society for Microbiology.
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4. Characterization of exopolymers of aquatic bacteria by pyrolysis-mass spectrometry.
Exopolymers from a diverse collection of marine and freshwater bacteria were characterized by pyrolysis-mass spectrometry (Py-MS). Py-MS provides spectra of pyrolysis fragments that are characteristic of the original material. Analysis of the spectra by multivariate statistical techniques (principal component and canonical variate analysis) separated these e
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5. Copper-binding characteristics of exopolymers from a freshwater-sediment bacterium.
Copper-binding activity by exopolymers from adherent cells of a freshwater-sediment bacterium was demonstrated by a combination of equilibrium dialysis and flameless atomic absorption spectrometry. Crude, cell-free exopolymer preparations containing protein and polysaccharide components bound up to 37 nmol of Cu per mg (dry weight). A highly purified exopoly
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6. Effect of bacterial extracellular polymers on the saturated hydraulic conductivity of sand columns.
Columns were packed with clean quartz sand, sterilized, and inoculated with different strains of bacteria, which multiplied within the sand at the expense of a continuous supply of fresh nutrient medium. The saturated hydraulic conductivity (HCsat) of the sand was monitored over time. Among the four bacterial strains tested, one formed a capsule, one produce
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7. Biosynthesis of Novel Exopolymers by Aureobasidium pullulans
Aureobasidium pullulans ATCC 42023 was cultured under aerobic conditions with glucose, mannose, and glucose analogs as energy sources. The exopolymer extracts produced under these conditions were composed of glucose and mannose. The molar ratio of glucose to mannose in the exopolymer extract and the molecular weight of the exopolymer varied depending on the
American Society for Microbiology.
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8. Effects of pH and Trace Minerals on Long-Term Starvation of Leuconostoc mesenteroides
Laboratory experiments have definitively shown that exopolymer-producing bacteria have the potential to modify the flow of fluids in oil reservoirs to enhance oil production. Once injected into the reservoir, they will be subjected to a wide range of pH values and to starvation resulting from nutrient depletion. For successful field implementation it is nece
American Society for Microbiology.
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9. Structure of Exocellular Polymers and Their Relationship to Bacterial Flocculation
Several gram-negative, polarly flagellated rods were isolated on the basis of their flocculent growth habit. Some of the isolates possessed a capsular matrix which is composed of exocellular fibrils. Other isolates did not appear to have a capsular matrix when examined with a bright-field microscope with or without the aid of stains. However, these latter ty
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10. Attachment Stimulates Exopolysaccharide Synthesis by a Bacterium
This study examined the hypothesis that solid surfaces may stimulate attached bacteria to produce exopolymers. Addition of sand to shake-flask cultures seemed to induce exopolymer synthesis by a number of subsurface isolates, as revealed by optical microscopy. Several additional lines of evidence indicated that exopolymer production by attached cells (in con
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11. Model system for studies of microbial dynamics at exuding surfaces such as the rhizosphere.
An autoclavable all-glass system for studying microbial dynamics at permeable surfaces is described. Standard hydrophobic or hydrophilic membranes (46-mm diameter) of various pore sizes were supported on a glass frit through which nutrient solutions were pumped by a peristaltic pump. The pump provided a precisely controlled flow at speeds of 0.5 to 500 ml of
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12. Relationship between Transport of Bacteria and Their Clogging Efficiency in Sand Columns
In an earlier article, we reported that, under conditions in which neither exopolymers nor bacterial mats were produced, Arthrobacter sp. strain AK19 was an effective plugging agent in sand columns, whereas the bacterial strain SLI- had no significant effect on the permeability of the medium. A laboratory experiment with sand columns was carried out to eluci