Navegando por Autor "Oliveira, Débora de"

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Assessment of two immobilized lipases activity and stability to low temperatures in organic solvents under ultrasound-assisted irradiation
(Springer, 2012-03) Batistella, Luciane; Ustra, Mara K.; Richetti, Aline; Pergher, Sibele Berenice Castellã; Treichel, Helen; Oliveira, J. V.; Lerin, Lindomar; Oliveira, Débora de
Both stability and catalytic activity of two commercial immobilized lipases were investigated in the presence of different organic solvents in ultrasound-assisted system. In a general way, for Novozym 435, the use of ethanol as solvent led to a loss of activity of 35% after 10 h of contact. The use of iso-octane conducted to a gradual increase in lipase activity in relation to the contact time, reaching a maximum value of relative activity of 126%. For Lipozyme RM IM, after 5 h of exposure, the enzyme presented no residual activity when ethanol was used as solvent. The solvents tert-butanol and iso-octane showed an enhancement of about 20 and 17% in the enzyme activity in 6 h of exposure, respectively. Novozym 435 and Lipozyme IM presented high stability to storage after treatment under ultrasound-assisted system using n-hexane and tert-butanol as solvents.
Immobilization of porcine pancreatic lipase in zeolite MCM 22 with different Si/Al ratios
(Elsevier, 2011-02-28) Calgaroto, Cléber; Scherer, Robison P.; Calgaroto, Selma; Oliveira, Jose Vladimir; Oliveira, Débora de; Pergher, Sibele Berenice Castellã
The use of zeolites as support for immobilization of enzymes has been a matter of great interest recently due to the potential properties of these materials. In this work, the MCM 22 zeolite with different Si/Al ratios (15, 25 and 50) was used as support for immobilization of porcine pancreatic lipase, assessing the effect of its structure on the immobilization yield and enzyme activity. Results showed that the material composition influenced significantly the immobilization process. Higher yields of immobilization and enzymatic activities were achieved when MCM 22 with Si/Al ratio of 25 was used as support. In general, results demonstrate the potential of MCM 22 as support for porcine pancreatic lipase immobilization.
Influence of process parameters on the immobilization of commercial porcine pancreatic lipase using three low-cost supports
(Elsevier, 2012-10) Scherer, Robison P.; Dallago, Rogério L.; Penna, Fábio G.; Bertella, Francile; Oliveira, Débora de; Oliveira, Jose Vladimir de; Pergher, Sibele Berenice Castellã
The use of lipases as biocatalysts has attracted much attention recently, but industrial application has been hindered mainly due to the high production cost, determined by the production yield and enzyme stability. Immobilization of biocatalysts in inert supports can ensure their use for several batches, making possible to build cost-effective processes. The objective of this work was to investigate the influence of immobilization time and enzyme to support mass ratio on the yield of immobilization and esterification activity of porcine pancreatic lipase. Higher immobilization yields (38.2%) were obtained for pillared montmorillonite, 120 min of immobilization and enzyme to support mass ratio of 2:0.5. The highest esterification activity (1403 U/g) was achieved using the montmorillonite, after 180 min of immobilization and enzyme to support ratio of 2:1. The characterization of the supports, free and immobilized enzyme on different supports made possible to elucidate the immobilization results through the knowledge of support features.
Nanopartículas de poli-hidroxibutirato-co-valerato como suporte para a imobilização da lipase de Candida antarctica fração B
(Sociedade Brasileira de Química, 2014-04) Fernandes, Ilizandra A.; Nyari, Nádia L. D.; Oliveira, José Vladimir de; Rigo, Elisandra; Souza, Maria Cristiane M. de; Gonçalves, Luciana R. B.; Pergher, Sibele Berenice Castellã; Oliveira, Débora de
This work evaluates the immobilization of Candida antarctica lipase (Fraction B) using poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) nanoparticles as support. The effects of immobilization time (30-150 min) and pH (5-10) on lipase loading were evaluated. The stability of the immobilized enzyme towards temperature (40, 60, and 80 ºC), reuse and storage (at 4 ºC) were also determined. Furthermore, to assess its potential application in a system of interest, the immobilized lipase was used as a catalyst in the esterification of geraniol with oleic acid. The results indicated a time of 120 minutes and pH of 7 as optimal for immobilization. A 21 hour exposure of the PHBV-lipase derivative to 60 ºC showed a 33% reduction of the initial activity while storage at 4 ºC led to a residual activity (5% of the original activity). The derivative was used without significant loss of activity for 4 successive cycles. The use of the immobilized lipase as a catalyst in the production of geranyl oleate led to about 88% conversion of the initial reactants to products
Natural montmorillonite as support for the immobilization of inulinase from Kluyveromyces marxianus NRRL Y-7571
(Elsevier, 2012-10) Coghetto, Chaline C.; Scherer, Robison P.; Silva, Marceli F.; Golunski, Simone; Pergher, Sibele Berenice Castellã; Oliveira, Débora de; Oliveira, J. Vladimir; Treichel, Helen
The objective of this study was to investigate the process of immobilization of inulinases using natural montmorillonite as inorganic support. The enzyme to buffer ratio of 3:10 and 10 min of immobilization led to the highest specific activity, 375.07 U/mg protein. The immobilized inulinase kept its activity after 1968 h under storage at low temperatures and after 456–1826 h at high temperatures. The pH value of 3.5 led to the highest specific activity. Km values of 1.46 and 0.38 mM, and vmax of 0.2487 and 0.2396 mol/L min, were obtained, respectively, for sucrose and inulin.
Screening of supports for immobilization of commercial porcine pancreatic lipase
(FapUNIFESP, 2011) Scherer, Robison; Oliveira, Vladimir; Pergher, Sibele Berenice Castellã; Oliveira, Débora de
The aim of this work is to report the performance of different supports for the immobilization of commercial porcine pancreatic lipase. The immobilization tests were carried out in several types of Accurel, activated alumina, kaolin, montmorillonite, ion exchange resins and zeolites. The characterization of the supports showed differences in terms of specific area and morphology. The characteristics of the supports influenced the amount of enzyme adsorbed, yield of immobilization and esterification activity of the resulting immobilized catalyst. The clays KSF and natural and pillared montmorillonites presented potential for use as support for lipase immobilization in terms of yield and esterification activity. Yields of immobilization of 76.32 and 52.01% were achieved for clays KSF and natural montmorillonite, respectively. Esterification activities of 754.03, 595.51, 591.88 and 515.71 U.g-1 were obtained for lipases immobilized in Accurel MP-100, Amberlite XAD-2, mordenite and pillared montmorillonite, respectively.

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Navegando por Autor "Oliveira, Débora de"