Purification and lyophillization of Lysozyme produced by marine microorganism

Cell-free supernatant with marine microorganism lysozyme was prepared by centrifugation of culture broth,ultrafiltration and concentration.The crude lysozyme was purified 41.98 fold to electrophoretic homogeneity with recovery of 21.7% and specific activity of 3 987.7 U/mg by extracting with ethanol,Superdex 75 10/300 chromatography and reversed-phase HPLC.The relative molecular weight of this lysozyme was 17.1 kD determined by SDS-PAGE electrophoresis.Preparations of lysozyme from native marine microorganism were formulated with different additives for lyophillization.The studied additives,including trehalose,sucrose and maltose,showed good protecting effect with trehalose showing the best performance for freeze-drying stabilization.Comparing with the native lysozyme in the absence of protective agents,the activity of the freeze-dried lysozyme treated by trehalose(0.5 mol/L) and Tween 80(20 mg/L) as protective agents retained more than 95% of the original activity.