| abstract |
The present invention is characterized by providing a treatment method for recovering and purifying polypeptides having immunoglobulin binding activity using a genetically modified organism, wherein, rather than relying on differences in polypeptide host or amino acid sequence, impurities comprising host-originating cell components, contaminant proteins, and nucleic acids are precipitated at high efficiency to a larger particle size, thereby allowing for improved filterability and improved productivity in chromatography processes. This purifying method for polypeptides having immunoglobulin binding activity is characterized by comprising: (1) a step for culturing a genetically modified organism that produces polypeptides having immunoglobulin binding activity; (2) a step for performing an acidic heat treatment upon one or more of culture liquid obtained in step (1), supernatant therefrom, a liquid suspension of microbes in the culture liquid, crushed microbe liquid obtained by crushing the microbes in the liquid microbe suspension, and crushed microbe supernatant obtained by removing the microbes from the crushed microbe liquid; and (3) a step for separating the precipitate. |