Study on liquid fermentation and solid Fermentation technology of nattokinase

The effects of liquid fermentation and solid fermentation on nattokinase activity produced by Bacillus natto No.ZN-4 strain were studied.The effects on producing nattokinase were compared between the two processes.The result showed that the optimum culture conditions of liquid fermentation were as follows:2% glucose,1% peptone,Na2HPO40.6%,NaH2PO40.1%,MgSO40.05%,CaCl20.02%;initial pH7.0;the inoculum size 3%;temperature 35℃.The nattokinase activity was 1903U/mL after 56 hour fermentation.The inoculate size,temperature,and time were studied in solid fermentation.The result showed the optimum culture conditions of solid fermentation were as follows:the inoculum size 10%;temperature 37℃.The nattokinase activity was 2200U/g after 48 hour.