Chin. Sci. Bull.

Nattokinase is a novel fibrinolytic enzyme, which is homologous to Subtilisin Carlsberg. In this paper, Subtilisin Carlsberg was taken as a model protein of nattokinase. Effects of pH, ionic strength concentration of isopropanol on the extraction of Subtilisin Carlsberg with AOT/isooctane reverse micelles system were investigated. Further, the process of reverse micelles extraction of nattokinase from fermentation broth was studied. By taking the reverse micelles of AOT/isooctane as extractant to perform a full extraction cycle, it was found that about eighty percent of the total activity of nattokinase in the fermentation broth could be recovered and the purification factor was about 2.5. Homologous protein could be reasonably used as model protein of a target protein.Nattokinase is a novel fibrinolytic enzyme, which is homologous to Subtilisin Carlsberg. In this paper, Subtilisin Carlsberg was taken as a model protein of nattokinase. Effects of pH, ionic strength concentration of isopropanol on the extraction of Subtilisin Carlsberg with AOT/isooctane reverse micelles system were investigated. Further, the process of reverse micelles extraction of nattokinase from fermentation broth was studied. By taking the reverse micelles of AOT/isooctane as extractant to perform a full extraction cycle, it was found that about eighty percent of the total activity of nattokinase in the fermentation broth could be recovered and the purification factor was about 2.5. Homologous protein could be reasonably used as model protein of a target protein