P Hb Hv
Mostrando 13-24 de 25 artigos, teses e dissertações.
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13. Fotofísica de compostos aromátaicos em microesferas de polímeros biodegradáveis / Photophysics of aromatic compounds in biodegradable polymeric microspheres
Desenvolveu-se, neste trabalho, uma metodologia que permitiu conhecer detalhes intermoleculares da microencapsulação, fundamentais na definição de parâmetros que controlam este processo. Foram preparadas microesferas biodegradáveis de poli(hidroxibutirato-hidroxivalerato) (P(HB-HV)), por meio de emulsificação o/w com evaporação de solvente, de inte
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 21/09/2007
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14. Estudo físico-químico de micropartículas compostas por P(HB-HV) e por blendas de P(HB-HV) e PCL contendo fármacos-modelo lipofílicos ionizáveis / Physico-Chemical Study of Microparticles Composed of P(HB-HV) and P(HB-HV)/PCL Blends Loaded with Ionizable Lipophilic Drug-Models
Micropartículas formadas por blendas de P(HB-HV) com PCL apresentam aumento da porosidade com o aumento do percentual de PCL. Considerando-se a influência de poros na velocidade de liberação de fármacos, bem como a ausência de estudos que correlacionem quantitativamente perfis de liberação e características morfológicas de micropartículas de P(HB-
Publicado em: 2007
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15. Estudo da miscibilidade, morfologia e propriedades mecânicas de blendas P(3HB)/P(3HB-co-3HV) e equilíbrio de fases em altas pressões de P(3HB) e P(3HB-co-3HV) em gases densos / Study of miscibility, morphlogy and mechanical properties of P(3HB)/P(3HB-co-3HV) bends and equilibrium of phases in high pressures of P(3HB) and P(3HB-co-3HV) in dense gases
Visando o desenvolvimento de materiais biodegradáveis com boas propriedades que os tornem viáveis em aplicações cotidianas, estudou-se nesse trabalho a miscibilidade, amorfologia e as propriedades mecânicas de blendas P(3HB)/P(3HB-co-3HV), bem como o comportamento de fases em altas pressões de P(3HB) e P(3HB-co-3HV) em gases densos. Foram utilizados do
Publicado em: 2006
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16. Efeitos da radiaÃÃo Gama no polÃmero biodegradÃvel Poli(HIDROXIBUTIRATO) e no copolÃmero Poli(Hidroxibutirato-co-Hidroxivalerato)
Poly(hydroxybutyrate), PHB, is a biodegradable commercial polyester manufactured in Brazil and biosynthesized by Alcaligenes eutrophus bacteria from sugar cane biosynthesis. The great number of petrochemical plastics has brought about attention to biodegradable polymers. PHB is a thermoplastic with good properties and an excellent option as commodity. On the
Publicado em: 2006
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17. The Composition a evaluate the polymer biodegradable produce for Burkholderia sacchari with the different substrates / Avaliação da composição de polímeros biodegradáveis produzidos por Burkholderia sacchari a partir de diferentes substratos
The bacterial production of polyesters belonging to the polyhydroxyalkanoate family (PHA) has generated biodegradable, biocompatible and environmentally friendly new materials. Properties and applications of PHA depend on monomer composition, which is dependent both on the substrate available and the metabolic apparatus of the PHA-producing microorganism. Bu
Publicado em: 2005
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18. High-Level Production of Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) by Fed-Batch Culture of Recombinant Escherichia coli
Fermentation strategies for production of high concentrations of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] with different 3-hydroxyvalerate (3HV) fractions by recombinant Escherichia coli harboring the Alcaligenes latus polyhydroxyalkanoate biosynthesis genes were developed. Fed-batch cultures of recombinant E. coli with the pH-stat feedin
American Society for Microbiology.
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19. Production of poly-(beta-hydroxybutyric-co-beta-hydroxyvaleric) acids.
Alcaligenes latus, Alcaligenes eutrophus, Bacillus cereus, Pseudomonas pseudoflava, Pseudomonas cepacia, and Micrococcus halodenitrificans were found to accumulate poly-(beta-hydroxybutyric-co-beta-hydroxyvaleric) acid [P(HB-co-HV)] copolymer when supplied with glucose (or sucrose in the case of A. latus) and propionic acid under nitrogen-limited conditions.
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20. 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
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21. A Novel Genetically Engineered Pathway for Synthesis of Poly(Hydroxyalkanoic Acids) in Escherichia coli
A new pathway to synthesize poly(hydroxyalkanoic acids) (PHA) was constructed by simultaneously expressing butyrate kinase (Buk) and phosphotransbutyrylase (Ptb) genes of Clostridium acetobutylicum and the two PHA synthase genes (phaE and phaC) of Thiocapsa pfennigii in Escherichia coli. The four genes were cloned into the BamHI and EcoRI sites of pBR322, an
American Society for Microbiology.
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22. Production of poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) in a recombinant Escherichia coli strain.
An Escherichia coli strain has been constructed that produces the copolymer poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) P(HB-co-HV). This has been accomplished by placing the PHB biosynthetic genes from Alcaligenes eutrophus into an E. coli fadR atoC(Con) mutant and culturing the strain in M9 minimal medium containing glucose and propionate. 3-Hydroxyvaler
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23. Role of fadR and atoC(Con) mutations in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) synthesis in recombinant pha+ Escherichia coli.
Recombinant Escherichia coli fadR atoC(Con) mutants containing the polyhydroxyalkanoate (PHA) biosynthesis genes from Alcaligenes eutrophus are able to incorporate significant levels of 3-hydroxyvalerate (3HV) into the copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)]. We have used E. coli fadR (FadR is a negative regulator of fatty acid
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24. Degradation of poly(3-hydroxyoctanoic acid) [P(3HO)] by bacteria: purification and properties of a P(3HO) depolymerase from Pseudomonas fluorescens GK13.
Twenty-five gram-negative bacteria and one gram-positive bacterium capable of growing on poly(3-hydroxyoctanoic acid) [P(3HO)] as the sole source of carbon and energy were isolated from various soils, lake water, and activated sludge. Most of the isolates degraded only P(3HO) and copolymers of medium-chain-length (MCL) hydroxyalkanoic acids (HA). Except for