Optimization,Isolation And Immunomodulatory Activity Of DHA From Schizochytrium Limanium

DHA as an important of unsaturated fatty acid,its characteristic is 6 unsaturated bond structure.DHA has a very important role on human health,which shows a lot of physiolog-ical functions such as brain bright eye,anti-cancer,anti-inflammatory and inhibiting aller-gic reaction,etc.Schizochytrium limanium is a kind of marine fungi,with fast growth,non-toxic and riched docosahexaenoic acid(DHA),etc.Schizochytrium limanium is an ide-al strain for the production of DHA.The activity study on the extraction of DHA from Schizochytrium limanium can make full use of DHA resources.This study adopted the single factor optimization method to optimize the culture con-ditions for Schizochytrium limanium,the results of the best culture conditions are the best quantity of 10%,pH of 6,glucose 60 g/L,peptone 25 g/L,sea crystal 28 g/L,VBI 0.1 mg/L,D-biotin 0.05 mg/L.The dry weight and fat content of Schizochytrium limanium were 10.61 g/L and 1.85 g/L,respectively.The content of fat accounted for 17.40%of the dry weight of Schizochytrium limanium.After optimized the culture medium,the dry weight and fat content were 22.71 g/L and 9.82 g/L,respectively.The content of fat ac-counted for 43.26%of the dry weight of Schizochytrium limanium,the dry weight and fat content were increased by 12.10 g/L and 7.97 g/L,respectively.The content of DHA was detected by Gas chromatography(GC),the result showed that before optimized the culture medium,the content of DHA in Schizochytrium limanium accounted for 10.31%of total 'fat content.After optimized the culture medium,the content of DHA in Schizochytrium limanium accounted for 19.26%of total fat content,which indi-cated that the content of DHA was obvious increased.Separated with silver nitrate-silica gel column by chromatography,the purity of obtained DHA is 92.86%.The immunomodu-latory activity of DHA was detected by MTT and cell stainings,etc.In a certain range of concentrations and action time,DHA could improve the proliferation and phagocytic activ-ity of RAW264.7 cells significantly,enhance the metabolic ability of cell nucleic acids and glycogen,increase the production of cell enzymes(acid phosphatase,lysozyme).