Purification of VP3 protein of infectious bursal disease virus using nickel ion-immobilized regenerated cellulose-based membranes

In this study, hexa-histidine tagged VP3 protein of infectious bursal disease virus (IBDV) was purified using immobilized metal ion affinity technique from the fermentation of Escherichia coli BL21 (DE3) containing a recombinant plasmid with a VP3 gene. The purification efficiencies of VP3 protein (TVP3 and ΔTVP3) using Ni2+-NTA commercial agarose gels and Ni2+-IDA regenerated cellulose-based membranes at 4 °C were compared. A good washing condition for removing most impurity proteins was found as 20 mM NaH2PO4, 500 mM NaCl, 40 mM imidazole, pH 7.8, whereas an efficient elution condition was 20 mM NaH2PO4, 500 mM NaCl, 500 or 750 mM imidazole, pH 7.8. By applying these conditions to the flow experiments, similar recovery (86–88%) and purity (98–99%) for VP3 were obtained in both gel column (1 ml gel) and membrane cartridge (four membrane disks) under the flow rate of 1.7 ml/min for protein loading and 2.7 ml/min for protein elution. Regarding that the membrane process exhibited some advantages such as shorter residence time and lower cost, a better process efficiency in a large-scale system could be expected for the Ni2+-IDA membranes.