title: Thermodynamic studies of partitioning behavior of lysozyme and conalbumin in aqueous two-phase systems.
abstract: The objective of this study was to determine the thermodynamic parameters (Delta(tr)G, Delta(tr)H and Delta(tr)S) associated with lysozyme and conalbumin partitioning in aqueous two-phases systems (ATPS). Influence of salt type and polyethylene glycol (PEG) concentrations on the partition coefficient of lysozyme and conalbumin from egg white was studied. The evaluated ATPS were composed of PEG 1500 and inorganic salts (sodium citrate and sodium sulfate) at a temperature of 25 degrees C and pH 7.0, with PEG 1500 g mol(-1) concentrations of 14%, 16% and 18% (mass basis). Partitioning of lysozyme in PEG-citrate ATPS was enthalpically driven, however the PEG-sulfate ATPS was entropically driven. The tested systems can be employed for the separation of these two proteins in egg white, due to the fact that lysozyme migrates toward the polymeric phase and conalbumin to the saline phase in both ATPS. A high recovery of conalbumin in the saline phase of the PEG-sulfate ATPS was determined to be enthalpically driven.
authors.affiliation: Separation Process Laboratory, Department of Food Technology, Federal University of Viçosa, P.H. Rolfs Av., s/n, 36570-000 Viçosa, MG, Brazil.
authors.forename: Rita de Cássia Superbi
authors.initials: Rde C
authors.lastname: de Sousa
authors.forename: Jane Sélia dos Reis
authors.initials: JS
authors.lastname: Coimbra
authors.forename: Luis Henrique Mendes
authors.initials: LH
authors.lastname: da Silva
authors.forename: Maria do Carmo Hespanhol
authors.initials: Mdo C
authors.lastname: da Silva
authors.forename: Edwin Elard Garcia
authors.initials: EE
authors.lastname: Rojas
authors.forename: Antonio António Augusto
authors.initials: AA
authors.lastname: Vicente
mesh_terms: D003207:Conalbumin / Q000737:chemistry* / Q000302:isolation & purification; D009113:Muramidase / Q000737:chemistry* / Q000302:isolation & purification; D011092:Polyethylene Glycols / Q000737:chemistry; D012995:Solubility; D013816:Thermodynamics
chemical_list: D003207:Conalbumin; D011092:Polyethylene Glycols; D009113:Muramidase