Navegando por Palavras-chave "Emulsification"

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    Estudo da produção de exopolímeros com atividade biossurfactante por microrganismos isolados do processo de compostagem de resíduos no Zoológico de São Paulo
    (Universidade Federal de São Paulo, 2015-07-04) Barros, Caroline de Almeida [UNIFESP]; Vasconcellos, Suzan Pantaroto de [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The biosurfactants are compounds produced by microorganisms that increase the bioavailability of apolar compounds promotes the stabilization of oil-water emulsions.These substances are biodegradable and less toxic if compared to synthetic surfactants. Bacteria that are able to produce biosurfactants have been increasingly used in bioremediation of hydrocarbon-contaminated areas. They act by increasing the solubility of pollutants and accelerating their biodegradation. In this sense, the present study began by the isolation of 544 bacteria from the composting process that is established at the São Paulo Zoo Park Foundation (SPZPF). These isolates were screened about their surfactant abilities through the drop collapse method, emulsification index (E24) and surface tension (Du Noüy method). In this context, it was selected two bacteria, FPZSP 342 and FPZSP 84, which showed promising results regarding their abitlity to produce biosurfactant exopolymers (EPS) ratios above 1.2 g EPS / g cells, emulsification indexes (E24) above 60 % and surface tension between 30 and 40 mN/m. Through LC-MS / MS analysis using micrOTOF QII Bruker system, it was observed that both EPS produced by the selected strains, had chemical structural characteristics similar to glycolipid mixtures. These glycolipids produced by the two strains were analysed in monolayer Langmuir assays, as a form to allow note future possibility of their use in activities that aim the dispersion or petroleum emulsification. Both strains were characterized by molecular techniques based on the amplification and sequencing analysis of the 16S rDNA gene. The strain FPZSP 84 was characterized as Bacillus subtilis, while FPZSP 342 was affiliated to Staphylococcus warneri. In conclusion, we could assume that the selected bacteria in this study were able to produce biosurfactant compounds with potential for future applications in bioremediation of petroleum-impacted areas.
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    Janus emulsions of bixa orellana oil
    (Taylor & francis inc, 2016) Leonardi, Gislaine Ricci; Silva, Marina Martines [UNIFESP]; Guimaraes, Carina Moreira [UNIFESP]; Perrechil, Fabiana de Assis [UNIFESP]; Friberg, Stig
    Janus emulsions of the oil from the Bixa orellana (BO) nut, silicone oil (SO), and an aqueous solution of Tween 80 were prepared by intense mixing and optical microscopy images were obtained of the drops. The results showed the expected disordered emulsion of large SO drops with a number of attached smaller drops of the vegetable oil, whose images were transformed to regular Janus drops by the shear, when the cover glass was applied. The drops with a large BO/SO volume ratio did not immediately form well-defined and topologically equal Janus drops due to kinetic factors. The microscopy image was used to evaluate the correct angles and radii by a mathematical rotation to form an image with a straight-line contact line.