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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...
Immobilization of commercial laccase on spent grain
Silva, Andreia Machado da; Tavares, Ana P. M.; Rocha, Cristina M. R.; Cristóvão, Raquel O.; Teixeira, J. A.; Macedo, Eugénia A.The aim of this work was to assess the possibility of using beer spent grain (a byproduct of beer’s brewing industry) as a carrier for laccase immobilization. Both adsorption (on spent grain – SG and on digested spent grain – DSG) and covalent binding (using glycidol and glycidol followed by ethylenediamine on DSG) were used. The effect of different immobilization conditions on the immobilization yields and rec...
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...
Laccase production by free and immobilized fungal mycelium of Trametes versicolor
Silvério, Sara; Moreira, Sérgio; Mussatto, Solange I.; Milagres, Adriane M. F.; Macedo, Eugénia; Teixeira, J. A.The production of laccase by free and immobilized mycelium of Trametes versicolor was evaluated. Fermentation experiments were carried out using a Trametes defined medium [1] supplemented with tween-80 (0.5%, w/v) and xylidine (30 μM) to stimulate and induce the secretion of extracellular enzyme. The support for the mycelium immobilization consisted in 0.3 cm3 cubes of synthetic fiber (Scotch Brite, 3M Spain, S...
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...
Comparing approaches for drug-like molecules solubility calculations
Mota, Fátima L.; Queimada, António; Pinho, Simão; Macedo, Eugénia A.Solubility has been recognized as one of the most important properties for designing separation and purification processes of complex molecules, such as active pharmaceutical ingredients. Experimental solubility data are usually needed for performing such design operations. However, frequently data are unavailable due to reduced amounts of sample, time limitations, or inherent complexities with experimental mea...
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