EQA - Artigos Publicados em Periódicos
URI permanente para esta coleçãohttps://rihomolog.furg.br/handle/1/1611
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- ItemRaw glycerol as substrate for the production of yeast biomass(De Gruyter, 2013) Santos, Elisane Odriosolla dos; Michelon, Mariano; Gallas, Julia Adornes; Kalil, Susana Juliano; Burkert, Carlos André VeigaThe possibility of using raw glycerol as a substrate for yeast biomass production as a source of proteins was investigated. Biomass concentration, protein content and total protein content of four yeasts (Yarrowia lipolytica NRRL YB-423, Candida lipolytica NRRL Y-1095, Candida utilis NRRL Y-900 and Candida rugosa NRRL Y-95) were determinate, comparing analytical grade glycerol and raw glycerol. Y. lipolytica NRRL YB-423 has been selected as promising for cultivation in a raw glycerol-based medium, mainly due to the higher biomass concentration in relation to the other strains. For this strain, four different culture media were tested. The best results were obtained with 50 g/L glycerol, 5.5 g/L ammonium phosphate, 5.5 potassium dihydrogen phosphate, 1 g/L ammonium sulphate, 0.25 g/L magnesium sulphate, 0.021 g/L calcium chloride dehydrate, 1 g/L yeast extract, 1 g/L peptone, pH adjusted to 5.5. In these conditions, it was possible to obtain 17.8 ± 0.6 g/L maximum biomass concentration, 18.2 ± 1.0% protein content and 3.1 ± 0.1 g/L total protein production. These results represent a 1.2-fold increase in biomass concentration, a 1.5-fold increase in protein content and a 1.9-fold increase in total protein production in relation to the results obtained with the previously medium composition.
- ItemOptimization of inulinase production by kluyveromyces marxianus using factorial design(2001) Kalil, Susana Juliano; Suzan, Rodrigo; Maugeri Filho, Francisco; Rodrigues, Maria IsabelFactorial design and response surface techniques were used to optimize the culture medium for the production of inulinase by Kluyveromyces marxianus. Sucrose was used as the carbon source instead of inulin. Initially, a fractional factorial design (25–1) was used in order to determine the most relevant variables for enzyme production. Five parameters were studied (sucrose, peptone, yeast extract, pH, and K2HPO4), and all were shown to be significant. Sucrose concentration and pH had negative effects on inulinase production, whereas peptone, yeast extract, and K2HPO4 had positive ones. The pH was shown to be the most significant variable and should be preferentially maintained at 3.5. According to the results from the first factorial design, sucrose, peptone, and yeast extract concentrations were selected to be utilized in a full factorial design. The optimum conditions for a higher enzymatic activity were then determined: 14 g/L of sucrose, 10 g/L of yeast extract, 20 g/L of peptone, 1 g/L of K2HPO4. The enzymatic activity in the culture conditions was 127 U/mL, about six times higher than before the optimization.
- ItemGalacto-oligosaccharides production using permeabilized cells of kluyveromyces marxianus(De Gruyter, 2010) Manera, Ana Paula; Costa, Fátima Aparecida de Almeida; Rodrigues, Maria Isabel; Kalil, Susana Juliano; Maugeri Filho, FranciscoGalacto-oligosaccharides are non-digestible carbohydrates and are recognized as important prebiotics for than stimulation of the proliferation of lactic acid bacteria and bifidobacteria in the human intestine. GOS can be produced by a transgalactosylation reaction catalysed by β-galactosidase enzyme, and microorganisms can be used as a source of β-galactosidase. In this work, a process for producing GOS using permeabilized cells of Kluyveromyces marxianus CCT 7082 was proposed. The effects of the concentrations of lactose and enzyme, temperature and pH were studied using a fractional design followed by a central composite rotatable design. The optimum conditions for galacto-oligosaccharides production were found to be: lactose concentration 500 g/L, enzyme concentration 10 U/mL, 45°C and pH 7.0. Under optimized conditions, the GOS concentration, yield and productivity were 83 g/L, 16.5% and 27.6 g/L.h, respectively.
- ItemStudies on the Adsorption of Inulinase from Kluyveromyces marxianus ATCC 16045 onto an Ion Exchange Resin(2006) Kalil, Susana Juliano; Pasotto, Marlei Barboza; Maugeri Filho, Francisco; Rodrigues, Maria IsabelThe adsorption of an extracellular inulinase directly onto an ion exchange resin from a clarified crude broth was investigated in this work. The enzyme inulinase was obtained from Kluyveromyces marxianus ATCC 16045 by fermentation in shaken flasks in a medium containing peptone, sucrose, yeast extract and K2HPO4 at pH 3.5, 30°C and 150 rpm for 48 hours. The final enzymatic activity was about 72 U mL–1. The crude broth filtrate was used for kinetic studies and for the adsorption isotherm of the extracellular inulinase from Kluyveromyces bulgaricus ATCC 16045 onto an ion exchange resin. The trials were carried out at pH 3.5 and 25°C in stirred tank reactors containing STREAMLINETM SP, developed for expanded bed adsorption. It was observed that the adsorption was well described by the Langmuir isotherm, and the values determined for Qm and Kd were 1,254 U mL–1 and 0.325 UmL–1, respectively. The kinetic parameters k1 (6.52 . 10–3 mL U–1 min) and k2 (2.09. 10–3 min–1) as well as the average values of 1.71 . 10–2 cm s–1 for the film coefficient (Ks) and 6.96 . 10–7 cm2 s–1 for the effective diffusion coefficient (Def), were determined using the experimental results and mathematical modelling.
- ItemA new approach to evaluate immobilization of B-galactosidase on eupergit c: structural, kinetic, and thermal characterization(2014) Braga, Anna Rafaela Cavalcante; Silva, Marceli Fernandes; Oliveira, José Vladimir de; Treichel, Helen; Kalil, Susana JulianoThis study aimed to evaluate B-galactosidase immobilization. For this purpose, the ionic strength of the buffer, reaction time, amount of the immobilization support, and pH were evaluated by a central composite design. Assay 8, which consisted of 1.5 mol L −1 phosphate buffer (pH 7.5) and a reaction time of 2 h, produced the maximum yield. Eupergit® C (400 mg) was subsequently use as an immobilization support. Immobilization kinetics wereinvestigated, and a significant increase in the yield was obtained after immobilization compared with that obtained from assay 8 (22.0 U mL −1 vs. 15.6 U mL −1). The enzyme efficiency of actuation was evaluated using o -nitrophenyl-B-d-galactopyranoside and lactose, with lactose providing better results. The reuse of B-galactosidase was evaluated, and more than 50% of the initial enzyme activity was maintained after five cycles of use. Enzyme characterization revealed that immobilization improved some aspects of the thermostability of B-galactosidase.
- ItemUtilização de resíduos agroindustriais em processo biotecnológico para produção de B-galactosidase de Kluyveromyces marxianus CCT 7082(2011) Manera, Ana Paula; Ores, Joana da Costa; Ribeiro, Vanessa Amaral; Rodrigues, Maria Isabel; Kalil, Susana Juliano; Maugeri Filho, FranciscoO objetivo deste trabalho foi avaliar a composição do meio de cultura para a produção da enzima B-galactosidase de Kluyveromyces marxianus CCT 7082 utilizando a técnica de delineamento experimental. A produção da enzima foi realizada em meio composto por soro de queijo, água de maceração de milho (AMM) e hidrolisado de levedura Prodex-lac® e sais. Foi realizado um planejamento experimental fracionário (25-1) para determinar as variáveis significativas na produção da enzima. Foram testadas diferentes concentrações de lactose presente no soro de queijo (10 a 70 g L-1), AMM (10 a 100 g L-1), Prodex-lac (4 a 20 g L-1), (NH4)2SO4 (0 a 10 g L-1) e o pH (5 a 7). As variáveis concentração de lactose, AMM e o pH apresentaram efeito estatisticamente significativo na atividade enzimática dentro das faixas estudadas, sendo estas variáveis empregadas num delineamento composto central rotacional para otimizar a produção da enzima. As faixas testadas foram: concentração de lactose de 40 a 100 g L-1, AMM de 10 a 120 g L-1 e pH de 3,5 a 6,5. As condições que resultaram em maior atividade enzimática (1400 U g-1) foram 70 g L-1 de lactose, 65 g L-1 de AMM, 4 g L-1 de Prodex-lac e pH 5, obtendo uma produtividade de 61 U L-1 h-1.
- ItemAdsorption of amyloglucosidase from aspergillus niger NRRL 3122 using ion exchange resin(2008) Manera, Ana Paula; Setsuko, Eliana Kamimura; Brites, Luciana Machado; Kalil, Susana JulianoAmyloglucosidase enzyme was produced by Aspergillus niger NRRL 3122 from solid-state fermentation, using deffated rice bran as substrate. The effects of process parameters (pH, temperature) in the equilibrium partition coefficient for the system amyloglucosidase - resin DEAE-cellulose were investigated, aiming at obtaining the optimum conditions for a subsequent purification process. The highest partition coefficients were obtained using 0.025M Tris-HCl buffer, pH 8.0 and 25ºC. The conditions that supplied the highest partition coefficient were specified, the isotherm that better described the amyloglucosidase process of adsorption obtained. It was observed that the adsorption could be well described by Langmuir equation and the values of Qm and Kd estimated at 133.0 U mL-1 and 15.4 U mL-1, respectively. From the adjustment of the kinetic curves using the fourth-order Runge-Kutta algorithm, the adsorption (k1) and desorption (k2) constants were obtained through optimization by the least square procedure, and the values calculated were 2.4x10-3 mL U-1 min-1 for k1 and 0.037 min-1 for k2 .
- ItemOndas ultrassônicas e pérolas de vidro: um novo método de extração de b-galactosidase para uso em laboratório(2008) Medeiros, Fabiana Oliveira de; Alves, Fernanda Germano; Lisboa, Cristiane Reinaldo; Martins, Daniela de Souza; Burkert, Carlos André Veiga; Kalil, Susana JulianoThe optimization of a traditional technique of cellular disruption by abrasion was carried out and a process using ultrasonic waves associated with glass pearls to extract β-galactosidase from Kluyveromyces marxianus proposed. In the first case, the effects of the diameter and weight of the pearls in relation to the volume of cellular suspension and amount of time for cellular disruption were evaluated. The efficiency of the new process of cellular disruption was evaluated by varying the length of time of sonification and comparing with the method of abrasion under the same conditions. The proposed method can be efficiently applied to obtain β-galactosidase at laboratory scale.
- ItemTecnologia enzimática para captura de co2 cultivo de microalga para obtenção de anidrase carbônica(2013) Ores, Joana da Costa; Fernandes, Sibele Santos; Amarante, Marina Campos Assumpção de; Silva, Bibiana Porto da; Kalil, Susana JulianoNos últimos tempos existe um forte interesse na estabilização da abundância atmosférica de CO2 e outros gases de efeito estufa para mitigar os riscos do aquecimento global. As estratégias de redução de emissões de CO2 incluem a redução do uso global de energia e o desenvolvimento de combustíveis livres ou com baixo teor de carbono. Outra estratégia que pode ser utilizada é a captura e sequestro de CO2 atmosférico, onde sistemas utilizando a anidrase carbônica tem sido amplamente estudados. Esta enzima encontra-se amplamente distribuída na natureza, sendo as microalgas uma fonte potencialmente atrativa desta biomolécula. Este trabalho apresenta a obtenção da anidrase carbônica a partir da biomassa da microalga marinha Dunaliella tertiolecta e sua aplicação na captura enzimática do CO2. Foi realizado o cultivo da microalga em meio Conway a temperatura de 25 °C e fotoperíodo 12 h claro/escuro. Foi realizado um acompanhamento em termos de biomassa e pH, sendo feita a extração da enzima e determinada a atividade enzimática ao final do cultivo. Obteve-se um extrato enzimático com uma atividade na ordem de 67 U/mg de biomassa e a enzima foi aplicada na captação enzimática do CO2 eficazmente.
- ItemCaracterização cinética e termodinâmica de β-galactosidase de Kluyveromyces marxianus CCT 7082 fracionada com sulfato de amônio(2012) Heidtmann, Renata Bemvenuti; Duarte, Susan Hartwig; Pereira, Lidiane Pereira de; Braga, Anna Rafaela Cavalcante; Kalil, Susana JulianoA β-galactosidase é uma enzima importante que atua na hidrólise da lactose, podendo ser empregada na obtenção de alimentos destinados a consumidores intolerantes a esse dissacarídeo. A levedura Kluyveromyces marxianus apresenta bom rendimento de crescimento, além de ser um micro-organismo seguro em aplicações industriais, e tem sido utilizada para produção da enzima por cultivo submerso. A β-galactosidase obtida foi fracionada com sulfato de amônio e caracterizada quanto a temperatura e pH ótimos, estabilidade térmica, valores D e z, e parâmetros cinéticos e termodinâmicos. A temperatura e pH ótimos foram de 45-50 °C e 7,0, respectivamente. A energia de ativação da reação enzimática foi de 9,8 kcal.mol–1 e da reação de desativação, 64,2 kcal.mol–1. Os valores de Km e Vmax obtidos foram de 3,7 mM e 99,0 U.mL–1, respectivamente. A energia livre de Gibbs reduziu com o aumento de temperatura, sendo a enzima mais estável a 30 °C (ΔG* = 106,8 kJ.mol–1). A entalpia foi de 313,04 kJ.mol–1 e a entropia 0,68 kJ.mol–1.k–1. O valor D confirmou que a enzima foi mais estável em temperaturas próximas de 30 °C (D = 11.513,0 min) e o valor z foi de 5,8 °C.