Study On The Immobilizing Technology Of Bacillus Natto Cells To Produce Nattokinase And Design For The Immobilized Bioreactor

In this paper, the immobilizing technology of Natto cells is studied on the following five aspects: the superiority of immobilized cells, the activity determination of nattokinase ,the separation of nattokinase ,the molecular of nattokinase, the designation of the device and the bioreactor.It is discovered that the immobilized cells can be used nineteen times at least in repeatedly. The fibrinolytic activity of immobilized cells is one point six times of free cells in the first broth.It is also discovered that Methylthioninium Chloride can be used to modified the traditional fiber plate .the fibrinolytic activity of the fermentation liquid is 7280IU/mg referred to the standard curve of Urokinase.Then the nattokinase is separated and purified by salting out, PI, acetone precipitating and chromatography. It is turned out that the acetone precipitating method is the best. But its loss percentage is more than the salting out method undergoing drying step. The enzymatic activity of the freeze drying raw product got by acetone precipitating is 302.627(IU/ mg), that got by salting out is 164.017 (IU/ mg). Their enzymatic yields are 31.1% and 39.1% respectively. The yield of the first chromatographied freeze drying nattokinase separated by acetone precipitating is 12.2%, That separated by salting out is 11.8%.Further study showed that the fibrocystic activity of the nattokinase chromatographied for the first time is increased by 799.750(IU/mg), and that for the second time is declined to 155.1(IU/ mg), although its purity is improved.The result of SDS-polyacrylamide gel electrophoresis (SDS-PAGE) turned out that a purified nattokinase has been got through two times chromatography. Its molecular is about 14.4kd.The designs for the bioreactor and a set of device for natto bacillus have also been studied.