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Laccase recovery with aqueous two-phase systems : enzyme partitioning and stabi...
Silvério, Sara C.; Rodríguez, Oscar; Tavares, Ana P. M.; Teixeira, J. A.; Macedo, EugéniaIn this work, the potential of several aqueoustwo-phase systems (ATPS) for laccaserecovery was evaluated. For this purpose, different types of ATPS were prepared and the partition coefficient of pure commercial laccase was determined in each one, at 23 °C. A total of 21 ATPS were investigated: 12 composed by a polymer and a salt and 9 composed by two different polymers. For polymer-salt ATPS, different composit...
Laccase production by free and immobilized mycelia of Peniophora cinerea and Tr...
Silvério, Sara C.; Moreira, Sérgio; Milagres, Adriane M. F.; Macedo, Eugénia A.; Teixeira, J. A.; Mussatto, Solange I.The production of laccase by immobilized mycelia of Peniophora cinerea and Trametes versicolor was studied. In an initial stage, experimental assays were performed in Erlenmeyer flasks using free and immobilized mycelium, and the performance of the fungal strains to produce the enzyme was compared. Both fungi adhered into the support material (a synthetic fiber), growing not only on the surface but also in the ...
Recovery of Peniophora cinerea laccase using aqueous two-phase systems composed...
Moreira, Sérgio; Silvério, Sara C.; Macedo, Eugénia A.; Milagres, Adriane M. F.; Teixeira, J. A.; Mussatto, Solange I.Aqueous two-phase systems (ATPSs) composed by UCON (ethylene oxide/propylene oxide copolymer) and potassium phosphate salts were for the first time evaluated in the recovery of Peniophora cinerea laccase from complex fermented medium. The ATPSs were obtained by combining the random copolymer UCON with KH2PO4, potassium phosphate buffer pH 7 or K2HPO4. According to the results, protein partition occurred predomi...
Lysozyme and bovine serum albumin partitioning in polyethylene glycol–phenylala...
Silvério, Sara C.; Ferreira, Luísa A.; Martins, J. A.; Marcos, João Carlos; Macedo, E. A.; Teixeira, J. A.Polyethylene glycol (PEG) with average molecular weight of 8000 was used as a model polymer and modified by introducing an amino acid (phenylalanine) in its hydroxyl terminals. The effect of different percentages of the conjugate polymer in relation to the total polymer on binodal curve of PEG-8000–potassium phosphate buffer (KPB), pH 7.2 aqueous two-phase systems and solute partitioning was explored. The parti...
(Liquid + liquid) equilibria of polymer-salt aqueous two-phase systems for lacc...
Lladosa, Estela; Silvério, Sara C.; Rodríguez, Oscar; Teixeira, J. A.; Macedo, E. A.Aqueous two-phase systems (ATPS) are recognized as very suitable techniques for the recovery of target solutes in biological applications. Three new phase diagrams of (UCON 50-HB-5100 + potassium citrate + water), (UCON 50-HB-5100 + sodium formate + water), and (UCON 50-HB-5100 + potassium formate + water) systems were measured at 23 C. The binodal curves were successfully described using the empirical equation...
Interference of some ATPS phase-forming components in protein determination by ...
Silvério, Sara C.; Moreira, Sérgio; Milagres, Adriane M. F.; Macedo, Eugénia A.; Teixeira, J. A.; Mussatto, Solange I.The interference of some specific aqueous two-phase system (ATPS) phase-forming components in bovine serum albumin (BSA) determination by the Bradford method was investigated. For this purpose, calibration curves were obtained for BSA in the presence of different concentrations of salts and polymers. A total of 19 salts [Na(2)SO(4), (NH(4))(2)SO(4), MgSO(4), LiSO(4), Na(2)HPO(4), sodium phosphate buffer (pH 7.0...
Liquid-liquid equilibria of UCON + (sodium or potassium) phosphate salt aqueous...
Silvério, Sara C.; Rodríguez, Oscar; Teixeira, J. A.; Macedo, EugéniaSix phase diagrams for UCON−phosphate salt aqueous two-phase systems (ATPSs), at 23 °C, are presented. The ATPSs were obtained combining UCON (a random copolymer of 50 % ethylene oxide and 50 % propylene oxide) and a phosphate salt (KH2PO4, K2HPO4, potassium phosphate buffer pH = 7, NaH2PO4, Na2HPO4, and sodium phosphate buffer pH = 7). Among the salts used, Na2HPO4 proved to be the most effective in ATPS form...
Gibbs free energy of transfer of a methylene group on {UCON + (sodium or potass...
Silvério, Sara C.; Rodríguez, Oscar; Teixeira, J. A.; Macedo, EugéniaThe Gibbs free energy of transfer of a suitable hydrophobic probe can be regarded as a measure of the relative hydrophobicity of the different phases. The methylene group (CH2) can be considered hydrophobic, and thus be a suitable probe for hydrophobicity. In this work, the partition coefficients of a series of five dinitrophenylated-amino acids were experimentally determined, at 23 °C, in three different tie-l...
Solute partitioning in polymer–salt ATPS : the collander equation
Silvério, Sara C.; Rodríguez, Oscar; Teixeira, J. A.; Macedo, EugéniaThe partition coefficients for several solutes (five nitrophenylated-monosaccharides and four proteins) were experimentally determined, at 23 ◦C, in three different tie-lines of two polymer–salt aqueous twophase systems (ATPS): UCON-K2HPO4 and UCON-NaH2PO4. These partition coefficients together with others obtained from the literature for five dinitrophenylated-amino acids were used to investigate the suitabili...
Relative hydrophobicity of (PEG or Ucon)-salt ATPSs
Silvério, Sara C.; Madeira, Pedro; Rodríguez, Oscar; Teixeira, J. A.; Macedo, EugéniaAqueous Two-Phase Systems (ATPSs) are biphasic systems composed mainly by water. ATPSs are obtained upon mixing of two aqueous solutions of certain polymers or a polymer and a salt (above certain critical conditions, e.g. concentration, temperature). These systems are commonly indicated for the extraction of biomolecules. In this work, the partition coefficients for a series of five dinitrophenylated amino-acid...
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