The Research And Development Of Silkworm Pupa Nattokinase Products By Bacillus Natto

The silkworm pupa contains various rich nutrients, especially the protein. So silkworm pupa was a good culture medium. The activity of decomposing thrombosis of Nattokinase was four times than plasmin. Nattokinase can regulate blood lipids, blood pressure and prevent atherosclerosis. The bacillus natto stiain JN-14of high activity which laboratory keep is used for fermentation. The research with silkworm pupae as raw materials contains three areas:Firstly solid fermentation of bacillus natto have been research. Secondly liquid fermentation of bacillus natto have been studied And then the liquid fermentation of bacillus natto have been enlarged by5L stirred tank fermenter.The experimentaL results indicate that:the optimized conditions of the solid fermentation of nattokinase(NK) production were confirmed:thickness of culture medium0.5cm, Gelcose2%, Geltin1%, inoculation quantity5%, incubation temperature37℃, incubation time24h. On this condition, the activity of NK(wet) was1020.2U/g.The mass ratio of wet and freeze-dried was2.96.the activity of freeze-dried powder was2970.17u/g and it was retained98.36%.Having been optimized by single-factor experiments, the best conditions of liquid fermentation were determined as2%soluble starch,1.4%silkworm pupa protein,0.5%CaCl2,0.05%K2HPO4,0.05%KH2PO4, initial pH7.0. The optimal fermented conditions were:15mL/100mL culture flask,2%inoculation quantity, shaking by190r/min, incubation temperature37℃,incubation time48h. About1502.22u/mL activity can be achieved. Fermentation of soluble solids contains12.42%. And freeze-dried powder of liquid fermentation activity was11028.78u/g which retained94.21%activity.Fermentation result of5L stirred tank fermenter were:rpm400r/pm, ventilation volume1.3L/min, incubation time48h.The activity of NK was1542.31u/mL.