Fermentation of Nattokinsae and Preparation of Freezd-dried Powder

The liquid fermentation process for nattokinase by Bacillus natto in 300L fermentor,and separation of nattokinase,and the temperature stability of nattokinase freezd-dried powder were studied.The results showed that,the liquid fermentation process should be stopped in 20hr according the relation of fermentation time and nattokinase activity and should control the foam because the foam made the nattokinase lose the activity.Nattokinase extract was acquired by ammoniun sulfate grade ricipitation,the activity of nattokinase freezd-dried powder was strongly protected by the presence of gelatin,was not significantly affected when the nattokinase freezd-dried powder was stayed 6 day at 60℃.