A process with two stages and intermediate ethanol concentrations resulted in greater effectiveness of freeze concentration. The ethanol used in the freeze concentration is of low cost and is easily eliminated in the drying process.

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The application of cryogels for biomolecule purification has expanded due to their adsorption efficiency and operational advantages. In this study, polyacrylamide cryogels functionalized with L-phenylalanine (cryogel-Phe) via the glutaraldehyde method were designed for lysozyme adsorption. Cryogel functionalization was confirmed by Fourier-transform infrared spectroscopy and Kjeldahl analysis, indicating the immobilization of 458.65 mg phenylalanine g cryogel À1 . Cryogel-Phe showed high porosity (0.95) and a Young's modulus of 526.71 kPa. Thermogravimetric analysis indicated that thermal degradation occurred above 200 C. Differential scanning calorimetry and X-ray diffraction confirmed that the cryogel material was amorphous. In addition, the column presented a hydraulic permeability of 4.15 Â 10 À13 m 2 , axial dispersion ranging from 10 À7 to 10 À6 m 2 s À1 , and a height equivalent to a theoretical plate ranging from 0.10 to 0.21 cm. The highest adsorption of lysozyme (67.65 mg g À1 ) was obtained using sodium thiocyanate saline solution (0.025 mol L À1 , pH 5.0). The ability of the cryogel-Phe column to capture and purify lysozyme was confirmed by high enzymatic activity (1294.17 U ml À1 ), purity (87.92%), purification factor (11.49), and sulphate-polyacrylamide electrophoresis gel (SDS-PAGE) electrophoresis gel.

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