Partição do glicomacropeptídeo usando sistemas aquosos bifásicos

• Autor(a) principal: Silva, César Augusto Sodré da
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2961
• topic: Sistemas aquosos bifásicos; Caseinomacropeptídeo; Bio- separações; Aqueous two-phase systems; Caseinmacropeptide; Bio- separation; CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::TECNOLOGIA DE ALIMENTOS

In this work, separation of glycomacropeptide (GMP) was studied using liquid-liquid extraction with aqueous two-phase systems (ATPS) composed by poly (ethylene glycol) (PEG) and an inorganic salt. This technique is an advisable purification process applied to large scale since it provides a selective partition with high yields. The partition behavior of GMP in ATPS was investigated studying the influence of the type of salt (potassium phosphate, sodium citrate, lithium sulfate or sodium sulfate), polymer molar mass (PEG1500, PEG2000, and PEG4000), phase concentrations (tie line length), sodium chloride addition, pH value, and temperature in the system in order to fit ratio of system to the separation. The partition coefficient was defined as the ratio of GMP concentration in the upper phase (PEG) and in the bottom phase (salt). It was observed that the protein partitioned almost in the top PEG-rich phase, where the prevalent non- protein contaminants are PEG and a little amount of the salt, which can easily be removed from the target protein by means of size exclusion chromatography technique. Among the systems analysed and due to citrates characteristics as a biodegravel and nontoxic compound, the extraction conditions which provided the best results were: PEG1500 with concentration of PEG of 15.00 mass % and sodium citrate with concentration of 18.91 mass %; at pH 8.0 and temperature of 318.15 K. In this system were found values of partition coefficient above 30 and approximately 94.66 % of GMP was recovered in the top phase, what demonstrates a good separation. In addition, thermodynamic parameters (ΔH◦, ΔS◦, ΔG◦) as a function of temperature, were calculated for the system PEG1500-sodium citrate at different PEG concentrations and the results imply thermodynamic differences between partitioning of GMP in this system. This study clearly showed that ATPS can be successfully used for recovery and initial purification of GMP.