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Item Biotechnological potential of yeast isolates from cachaça : the Brazilian spirit.(2015) Conceição, Luís Eduardo Fernandes Rodrigues da; Saraiva, Margarete Alice Fontes; Diniz, Raphael Hermano Santos; Oliveira, Juliana; Barbosa, Gustavo Dimas; Alvarez, Florencia; Correa, Lygia Fátima da Mata; Mezadri, Hygor; Coutrim, Maurício Xavier; Afonso, Robson José de Cássia Franco; Lucas, Cândida Manuel Ribeiro Simões; Castro, Ieso de Miranda; Brandão, Rogélio LopesThis study identified phenotypic traits appropriate for biotechnological applications of 118 yeasts isolated from cachaça distilleries. Different properties were verified: capacity to use alternative carbon sources; ability to tolerate high concentrations of sucrose, ethanol, methanol, aluminum and zinc as well as different pH values and foam production. Pichia guilliermondii and Pichia anomala strains were identified as the most promising ones for application in the second-generation biofuel industry, showing ability to grow on high glycerol concentrations. Other isolates, identified as Saccharomyces cerevisiae, produced bioethanol comparable to the industrial strains, and were therefore ideal for use in the first-generation ethanol industry. Some of these strains also showed high resistance to aluminum, as observed in sugarcane juice, and to intercycle washings with diluted sulphuric acid, as performed in the industrial bioethanol production process. In summary, yeast isolates from cachaça distilleries displayed robustness and phenotypic plasticity, which makes them interesting for biotechnological applications.Item Spectrofluorimetric determination of second critical micellar concentration of SDS and SDS/Brij 30 systems.(2009) Romani, Ana Paula; Machado, Antonio Eduardo da Hora; Hioka, Noboru; Severino, Divinomar; Baptista, Mauricio da Silva; Codognoto, Lúcia; Magini, Maira Regina Rodrigues; Oliveira, Hueder Paulo Moisés dePotentially useful stead-state fluorimetric technique was used to determine the critical micellar concentrations (CMC1 and CMC2) for two micellar media, one formed by SDS and the other by SDS/Brij 30. A comparative study based on conductimetric and surfacial tension measurements suggests that the CMC1 estimated by the fluorimetric method is lower than the value estimated by these other techniques. Equivalent values were observed for SDS micelles without Brij 30 neutral co-surfactant. The use of acridine orange as fluorescent probe permitted to determine both CMC1 and CMC2. Based on it an explanation on aspects of micelle formation mechanism is presented, particularly based on a spherical and a rod like structures.Item Nanomagnetism and domain structure of sintered nickel-zinc ferrites studied by magnetic force microscopy.(2004) Dias, AndersonThe nanomagnetic structure of hydrothermal NiZn femtes sintered at various temperatures was studied in this work through Magnetic Force Microscopy using different magnetically characterized tips. The magnetic patterns varied according to the tip employed and were correlated to the magnetic induced field generated by these different coated tips. Nickel fenites were produced at 200°C by hydrothermal synthesis and sintered at temperatures ranging from 1100°C to 1400°C.