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URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11847
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Item Spectroscopic and thermodynamic properties of Debaryomyces hansenii UFV-1 α-galactosidases(International Journal of Biological Macromolecules, 2010-04-01) Rezende, Sebastião T.; Viana, Pollyanna A.; Meza, Andreia N.; Gomide, Felipe T.F.; Nagem, Ronaldo A.P.; Santos, Alexandre M.C.; Santoro, Marcelo M.; Guimarães, Valéria M.Spectroscopic and thermodynamic properties were determined for Debaryomyces hansenii UFV-1 extracellular and intracellular α-galactosidases. α-Galactosidases showed similar secondary structure compositions (α-helix, β-sheet parallel and β-turn). Effects of pH and temperature on the structure of α-galactosidases were investigated using circular dichroism spectroscopy. It was more pronounced at low pH. Microcalorimetry was employed for the determination of thermodynamic parameters. Immediate thermal denaturation reversibility was not observed for α-galactosidases; it occurred as a thermodynamically driven process. Extracellular α-galactosidase, at pH 5.5, showed lower Tm when compared to the intracellular enzyme. The CD and DSC data suggest that D. hansenii α-galactosidases have different behaviors although they possess some similar secondary structures.Item Activity of Debaryomyces hansenii UFV-1 a-galactosidases against a-D-galactopyranoside derivatives(Carbohydrate Research, 2011-04-01) Rezende, Sebastião T. de; Viana, Pollyanna A.; Alves, Arianne de A.; Manfrini, Rozângela M.; Alves, Ricardo J.; Bemquerer, Marcelo P.; Santoro, Marcelo M.; Guimarães, Valéria M.α-d-Galactopyranosides were synthesized and their inhibitory activities toward the Debaryomyces hansenii UFV-1 extracellular and intracellular α-galactosidases were evaluated. Methyl α-d-galactopyranoside was the most potent inhibitor compared to the others tested, with values of 0.82 and 1.12 mmol L−1, for extracellular and intracellular enzymes, respectively. These results indicate that the presence of a hydroxyl group in the C-6 position of α-d-galactopyranoside derivatives is important for the recognition by D. hansenii UFV-1 α-galactosidases.Item Hydrolysis of soybean isoflavones by Debaryomyces hansenii UFV-1 immobilised cells and free β-glucosidase(Food Chemistry, 2014-03-01) Maitan-Alfenas, Gabriela P.; Lage, Lorena G. de A.; Almeida, Maíra N. de; Visser, Evan M.; Rezende, Sebastião T. de; Guimarães, Valéria M.An intracellular β-glucosidase from Debaryomyces hansenii UFV-1 was produced in an YP medium with cellobiose as the carbon source. This enzyme was purified, characterised and presented a Mr of 65.15 kDa. Yeast cells containing the intracellular β-glucosidase were immobilised in calcium alginate. The free β-glucosidase and immobilised cells containing the enzyme presented optima values of pH and temperature of 6.0 and 45 °C and 5.5 and 50 °C, respectively. The free enzyme maintained 62% and 47% of its original activity after 90 days at 4 °C and after 15 days at room temperature, respectively. The immobilisation process resulted in higher enzyme thermostability at 45 and 50 °C. Soy molasses treatment with the free enzyme and the immobilised cells containing β-glucosidase, for 2 h at 40 °C, promoted efficient hydrolysis of isoflavone glicosides to their aglycon forms. The results suggest that this enzyme could be used in the food industry, in the free or immobilised forms, for a safe and efficient process to hydrolyse isoflavone glycosides in soy molasses.