Method for increasing the content of docosahexaenoic acid in fat-containing materials or in fats and oils

Abstract

To provide a fat-and-oil in which the content of docosahexaenoic acid is increased. A process for producing highly unsaturated fatty acids comprising culturing a stramenopile capable of producing highly unsaturated fatty acids in a culture medium containing an inhibitor for fatty acid desaturases; fats-and-oils in which the content of highly unsaturated fatty acids, particularly docosahexaenoic acid produced by the relevant method, is increased. A method for enhancing the productivity of highly unsaturated fatty acids in stramenopiles, comprising culturing a stramenopile in a culture medium containing an inhibitor for fatty acid desaturases; stramenopiles having the enhanced productivity of highly unsaturated fatty acids, generated by the relevant method. Particularly, the process for producing highly unsaturated fatty acids, the method for enhancing the productivity of highly unsaturated fatty acids, and the stramenopile having the enhanced productivity of highly unsaturated fatty acids, wherein the stramenopile is a microorganism classified into Labyrinthulea.

What is claimed is: 
     
         1 . A fat-and-oil in which the content of docosahexaenoic acid is increased, said docosahexaenoic acid being produced by a method for increasing the content of docosahexaenoic acid in fat-containing materials or in fats and oils using a stramenopile as a microorganism capable of producing highly unsaturated fatty acids in producing fat-containing meterials containing long-chain highly unsaturated fatty acids or fats and oils containing long-chain highly unsaturated fatty acids with microorganisms, the method comprising culturing a stramenopile in a medium to which an inhibitor for fatty acid desaturases is added, to enhance the productivity of highly unsaturated fatty acids in the stramenopile. 
     
     
         2 . A stramenopile having the enhanced productivity of highly unsaturated fatty acids, generated by a method for enhancing the productivity of highly unsaturated fatty acids in stramenopiles, which method comprises culturing a stramenopile in a culture medium containing an inhibitor for fatty acid desaturases. 
     
     
         3 . A stramenopile as claimed in  claim 2 , wherein the stramenopile is a microorganism classified into  Labyrinthulea.    
     
     
         4 . A stramenopile as claimed in  claim 3 , wherein the microorganism classified into  Labyrinthulea  is one belonging to  Labyrinthula, Althornia, Aplanochytrium, Japonochytrium, Labyrinthuloides, Schizochytrium, Thraustochytrium,  or  Ulkenia.    
     
     
         5 . A stramenopile as claimed in  claim 2 , wherein the productivity of highly unsaturated fatty acids is that of docosahexaenoic acid.