Poly Beta Hydroxybutyrate
Mostrando 1-12 de 43 artigos, teses e dissertações.
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1. Cloning and heterologous expression of genes responsible for synthesis of polyhydroxybutyrato em Bradyrhizobium elkanii / Clonagem e expressão heterologa dos genes responsaveis pela sintese de polihidroxibutirato em Bradyrhizobium elkanii
Polyhydroxyalkanoates (PHAs) are polymers of hydroxyalkanoate acids, produced and accumulated intracellularly as a source of carbon and energy storage material, in prokaryotic cells. Often, the PHAs accumulation occurs in conditions when the carbon source is in excess but one or several other nutrients are limited, and may represent up to 80% of the cell dry
Publicado em: 2009
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2. Estudo das propriedades e biodegradabilidade de blendas de poliéster/amido submetidas ao ataque microbiano
This work deals with the biodegradation of blends of poly(beta-hydroxybutyrate)/starch and poly(beta-hydroxybutyrate-co-hydroxyvalerate)/starch. The blends were obtained by evaporation of the solvent in the mixture of the polymers in chloroform. Tests were carried out in presence of micro-organisms which acted as biodegradation agents. The blends were consum
Química Nova. Publicado em: 2007
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3. Accumulation of poly-beta-hydroxybutyrate in Spirulina platensis.
Poly-beta-hydroxybutyrate has been identified in the cyanobacterium Spirulina platensis. The addition of reduced carbon compounds to the growth medium was not required for poly-beta-hydroxybutyrate accumulation. Poly-beta-hydroxybutyrate accumulated during exponential growth to 6% of the total dry weight and then decreased during the stationary phase.
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4. D-(-)-poly-beta-hydroxybutyrate in membranes of genetically competent bacteria.
D-(-)-Poly-beta-hydroxybutyrate is a constituent of the membranes and the cytoplasms of genetically competent Azotobacter vinelandii, Bacillus subtilis, and Haemophilus influenzae cells. Within each species the concentration of D-(-)-poly-beta-hydroxybutyrate in the membranes and cytoplasm correlates with transformability. Fluorescence analysis of the thermo
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5. Nile blue A as a fluorescent stain for poly-beta-hydroxybutyrate.
Poly-beta-hydroxybutyrate granules exhibited a strong orange fluorescence when stained with Nile blue A. Heat-fixed cells were treated with 1% Nile blue A for 10 min and were observed at an excitation wavelength of 460 nm. Glycogen and polyphosphate did not stain. Nile blue A appears to be a more specific stain for poly-beta-hydroxybutyrate than Sudan black
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6. Poly-beta-hydroxybutyrate membrane structure and its relationship to genetic transformability in Escherichia coli.
The effects of competence-inducing treatments on the composition and organization of membrane lipids in Escherichia coli K-12, DH1, DH5, HB101, and RR1 were investigated for two widely used protocols in which transformability is developed at low temperatures in Ca2+ buffers. At stages during each procedure, the lipid compositions of the cells were determined
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7. Occurrence of poly-beta-hydroxybutyrate in Spirulina species.
Several strains of photoautotrophically grown Spirulina spp. contained poly-beta-hydroxybutyrate (PHB) at concentrations never exceeding a few milligrams per gram of dry weight. Under mixotrophic growth conditions in the presence of acetate, PHB reached values greater than 2.5% of dry weight. With pyruvate, no significant effect on PHB accumulation was obtai
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8. Relationship between butirosin biosynthesis and sporulation in Bacillus circulans.
The relationship between butirosin biosynthesis and certain biochemical characteristics related to sporulation in a strain of Bacillus circulans NRRL B-3313 was examined. The cellular content of dipicolinic acid increased while the amount of poly-beta-hydroxybutyrate decreased with changes in antibiotic productivity. Oligosporogenous mutants failed to synthe
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9. Poly-beta-hydroxybutyrate depolymerases of Pseudomonas lemoignei.
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10. Immunocytochemical analysis of poly-beta-hydroxybutyrate (PHB) synthase in Alcaligenes eutrophus H16: localization of the synthase enzyme at the surface of PHB granules.
Antibodies raised against the Alcaligenes eutrophus poly-beta-hydroxybutyrate (PHB) synthase polypeptide were used for immunocytochemical localization of the synthase enzyme in whole cells and purified PHB granules. The data presented demonstrate for the first time that the synthase enzyme is located on the surface of the PHB granule rather than being incorp
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11. Poly-beta-hydroxybutyrate in the chemolithotrophic bacterium Ferrobacillus ferrooxidans.
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12. Biodegradability and mechanical properties of poly-(beta-hydroxybutyrate-co-beta-hydroxyvalerate)-starch blends.
Wheat starch granules and poly-(beta-hydroxybutyrate-co-beta-hydroxyvalerate) [P(HB-co-HV), (19.1 mol% HV)] were blended at 160 degrees C. Increasing the starch content from 0 to 50% (wt/wt) decreased the tensile strength of P(HB-co-HV) from 18 MPa to 8 MPa and diminished flexibility as Young's modulus increased from 1,525 MPa to 2,498 MPa, but overall mecha