Studies On The Preparation Of Cellulose Metal-chelated Affinity Membrane And Its Application

Immobilized metal ion affinity membrane is a useful technology for the purification of many interesting biomolecules in recent years. It synthetized the virtue of affinity chromatography and membrane technology, so that some bulk and low content biotechnology products could be produced in factory scale. In this paper, affinity membrane was successfully prepared with cellulose anaLyis filter paper as support, and the process, adsorption of proteins and purification of functionality proteins from egg white were studied.Orthognal experiment of activeagent epichorohydin (EPI) showed that the temperature and consistence of lye were very important factors which affected the crosslinking and activation.The best reaction conditions were 4.0 mol/L(lye), 70 ℃, soakage and reaction time were both 45 min. Orthognal experiments of iminodiacetic acid (IDA) linkage showed that the dosage of IDA was an more important factor than temperature and time. The best conditions of IDA linkage were 25 mg IDA/cm² membrane, 60 ℃ and 15 h.The isothermal adsorption for bovine serum albumin (BSA) could be expressed by the Langmuir adsorptiong model, and the most adsorbable capacity of affinity membrane was 59.52 mg / g dry membrane. Affinity membranes with Fe³⁺ , Ni²⁺, Zn²⁺, Cu²⁺ metal—chelated ligand respectively, were used for adsorption — desorption experiments of Lf, Ly and BSA, experimental results showed that membrane with Cu²⁺ has higher adsorption capacity than those with Fe³⁺, Ni²⁺, Zn²⁺, and could be reused well.Cu²⁺ metal—chelated affinity membrane has the best effect on the purification of functional proteins from egg white, ovotransferrin and Lyozyme could be purified by two-step elution, and it afforded an more easy technique for membrane separation and industrialization in the future.Studies on the solubility of ferric iron indicated that ovotransferrin could increase the solubility of ferric iron in the presence of phosphate, and trivalence has better effect than bivalence. Antibacterial activity of this substance were also studied, it showed that they could restrain the growth of E.Coli and salmonella, and could be used as availability element in the functional food.