| Natto is a kind of traditional soybean fermented food in japan. It is manufactured by mixing steam soybean,inoculating Bacillus Natto to the mixture and culturing under definite temperature and humidity.it is considered the secrect of longevity of Japanese.Natto have a large number of nutritional and hygienical value.the protein is 31.2g;fat is 19.9g;carbohydrate is 22.8g;Ca is 331mg ;P is 503mg;Fe is 13.7mg per 100g natto.and the protein of natto include all the pre-requisite amino acid,can be compared with beef.upwards of 50% is water-solubility protein.there are a great deal of unsaturated fatty acid,lipid, lecithin,vitaminB,especially the vitaminb12,etc.eating natto frequently will have fuction of antioxidant;antidoat;dissolving thrombustic,antitumom,depressing blood pressure etc.Nattokinase(NK) is a serine protease enzyme that is extracted from a traditional fermented food in Japan.it is finded by xujianyanghang doctor in 1987.It is reported that NK have a strong thrombustic function.compared with the thrombolytic agents such as streptokinase urokinase and recombinanttissue typeplasminogen activator ,nattokinase is safer and easier to be absorbed .nattokinase has low molecular weight ,more direct and persistent effect on thrombosis.at the same time, it can be fermented by bacteria,which will lower the production cost. So nattokinase can be developed as a new fibrinolytic medicine.This paper study on the the solid fermentation of Nattokinase,purification,and the application of natto and nattokinase.At last,the main results are as follows:We get six Bacillus Natto strains from the natto of Japanese market,together with two strains from chenglai graduate school ;one strains from holand friend stored in lab ,we compared the ability to produce nattokinase and superoxide .a strain was selected and named NK-6,which have capability of producing high yield of NK and SOD basing on a simple solid medium.another strain was selected and named NK-4,which have capability of producing high yield of NK basing on a simple solid medium.Using NK-6 ,The solid fermentation was optimized. The optimal condiction : inoculation quantity,4%.culture time,26h.salt: sugar =2:1.salt,4%;the taste of natto is good ,noammonia's taste,it is suitable to Chinese.The medium components and fermentation conditions for the nattokinase production by Bacillus Natto solid fermentation were studied.The operating factors including the thicking of soybean,initial water content,fermentation time,appendant carbon and conditions were determined as flow:the thickness of materials 2.0cm;natural initial pH;culture temperature,37 °C .relative humidity,60%-70%;and fermentation time ,24h.the fermentation medium was optimized by single factors and prthogonal experiments:50gsoybean,lg maltose,lg galactose and 50% initialwater content.the optimized condiction allowed the NK production to be increased from lOOOIU/g to 2250IU/g dry soybean.it is about higher twice than initial production.In order to increase the fibrinolytic activity of nattokinase, the crude extract of natto was purified by using sephadexG50 chromatography, fibrinolytic activity fractions were selected through tube method. Fibrinolytic activity of nattokinase was measured according to the fibrin plate method. The molecular weight of nattokinase were evaluated in SDS-PAGE after isolation and purification. Effective purification procedures of NK were studyed by (NH4)2SO4 fraction precipitation and gel filtration chromatography.The optimal saturated concentration of(NH4)2S04 was 35% and 70%, the optimal conditions of gel filtration chromatography were that the velocity 0.5ml/minl. the result shows the enzyme activity recovery is 42.1%, purification folds is 19.At last,we considered the application of natto and nattokinase.we got two kinds of products and designed several products formation.we provided the groundwork and application project to impulse the process of industrialistion of novel soybean products. |
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