Method development for direct recovery of lysozyme from highly crude chicken egg white by stirred fluidized bed technique

An improved procedure was developed involving a stirred fluidized bed (SFB) adsorption for direct capture of lysozyme from unclarified preparations of chicken egg whites (CEW). The maximal binding capacity of Streamline SP adsorbent for lysozyme was observed at pH 4. A typical adsorption isotherm curve for lysozyme in crude CEW was well correlated with the Freundlich model. For an initial concentration of 20 mg CEW/ml, adsorption approached equilibrium after 30 min. Determination of dynamic binding capacity for lysozyme in a stirred fluidized bed column (i.d. 2.5 cm) was carried out using frontal analysis. The maximal loading volume of crude CEW feedstock (20 mg/ml) at 1% breakthrough for lysozyme was approximately 5, 22, and 28-fold settled bed volumes, corresponding to 256, 2173, and 4125 ml CEW, respectively. Optimal conditions for elution scheme were determined in small packed bed experiments conducted with clarified CEW. Further experiments were carried out to assess the feasibility of using Streamline SP adsorbent and SFB column for direct recovery of lysozyme from highly crude CEW (20 mg/ml in 20 mM sodium acetate buffer at pH 4). It was found to be successful in achieving purification of lysozyme in a high yield of 98% with a purification factor of 11 in a single step. The specific activity (7.80 x 10(4) U/Mg) was higher than that obtained with a commercially available pure sample of lysozyme (Sigma, 7.30 x 10(4) U/Mg). (c) 2006 Elsevier B.V. All rights reserved.