Abstract: This experiment studied the method of separating and purifying immunoglobulin from the yolk of highly immuned hens, and established the optimized conditions: the yolk was diluted 10 times with aseptic water, regulated to pH 5.3, frozen at -18℃ for 6h, then thawed at 4℃. The thawed yolk solution was added with 3% diatomaceous earth, and filtered through 0. 45μm cellulose acetate membrane. Then the solution was concentrated 5 times through the way of Ultraflitration (5MWCO) and precipitated with 45% saturated ammonium sulfate under the condition of pH 5.3. In the end, it was separated and purified again through DEAE-Sepharose F.F. Column after the sediment was redissolved. The result showed that electrophoreticaly pure IgY could be obtained from the yolk of immuned hens and the Total Activity Recovery could reach 64.16%.

Key words: IgY, microfiltration, ultrafiltration, anion exchange chromatography