Liquid–liquid equilibrium (LLE) data were obtained for aqueous two-phase systems composed of polyethylene glycol (PEG) 400 g mol–1 + organic salt (Na2SO4) + water at different temperatures (293.15, 298.15, 303.15 and 308.15)/K, and pH values of 3.0, 4.0, and 5.0. The effect of temperature and pH on the binodal curves were evaluated, and it was verified that the increase of the variables resulted in a larger biphasic region. The salting-out effect was studied using the values of parameters of the effective excluded volume (EEV) model. The experimental results of LLE have been correlated using the UNIFAC model. The root-mean-square deviations between the experimental and predicted LLE compositions for the PEG 400 + Na2SO4 systems were very low. The UNIFAC model was able to represent satisfactorily the aqueous two-phase systems studied.

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The use of macroporous monolithic matrices in the purification of biocompounds is constantly growing and developing. In this work, the objective was to optimize the quantity of N-acetyl-D-glucosamine (D-GlcNAc) immobilized on the surface of macroporous polymeric cryogels for capture of lectins from less clarified solutions. Surface response methodology was applied and it was observed that the immobilization temperature of the glutaraldehyde (GLU) and the D-GlcNAc concentration influenced the amount of sugar immobilized. The matrices produced with 1.1% of allyl glycidyl ether were functionalized by GLU. Optimal maximum condition was obtained with mean value of 160.39 AE 26.38 mg of D-GlcNAc immobilized per gram of dry cryogel. Characterization analyses of the matrices showed that the activation process was effective, maintaining the macroporous structure and physical characteristics. The adsorbents produced were tested for capture of lectins from a crude protein solution of barley. At tested conditions, adsorbent capture around 11% of protein in solution but reduce the hemaglutinating capacity in 40%, demonstrating its selectivity. The cryogels functionalized with D-GlcNAc present potential for use in capture compounds by affinity with carbohydrates, such as lectins.