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Recovery of lysozyme from aqueous solution by polyelectrolyte precipitation with sodium alginate

Sun, Xin, Xiao, Jun-Xia, Huang, Guo-Qing
Food hydrocolloids 2019 v.90 pp. 225-231
aqueous solutions, coprecipitation, dissociation, electrolytes, electrostatic interactions, hydrocolloids, lysozyme, pH, sodium alginate, sodium chloride, thermal stability
Lysozyme was recovered from its aqueous solution by coprecipitation with sodium alginate. Electrostatic interaction between the two polyelectrolytes could occur between pH 2.0–9.0 and peaked at pH 3.0. The maximum lysozyme recovery of 97.10% was recorded at a mass ratio to sodium alginate of 2:1 and the presence of excessive sodium alginate reduced lysozyme precipitation. Complexation at pH 3.0 conferred the most compact and elastic network structure for the complex, but reduced the thermal stability and caused the greatest structural variation to lysozyme. The complexes separated at pH 4.5 and 6.0 could be dissolved by 1.0 mol/L NaCl, but that at pH 3.0 released only 77% lysozyme and further increase of NaCl concentration could not promote lysozyme liberation. It was concluded that coprecipitation with sodium alginate was potential in recovering lysozyme from its aqueous solutions and the dissociation of resultant complexes should be further enhanced to increase yield.