Method of producing microbial oil containing fatty acids obtained from stramenopile

Abstract

A method for producing a microbial oil includes the steps of: genetically modifying a labyrinthulid by disrupting and/or silencing a gene, or by transforming another gene in addition to the disruption and/or gene silencing of the gene; culturing the labyrinthulid, such that a fatty acid composition accumulated in the labyrinthulid comprises an increased EPA content; and collecting the microbial oil having the increased EPA content from the labyrinthulid. The increased EPA content is not less than 3.3% of a total fatty acid composition.

What is claimed is: 
     
         1 . A method for producing a microbial oil, comprising:
 genetically modifying a labyrinthulid by disrupting and/or silencing a gene, or by transforming another gene in addition to the disruption and/or gene silencing of the gene;   culturing the labyrinthulid, such that a fatty acid composition accumulated in the labyrinthulid comprises an increased EPA content; and   collecting the microbial oil having the increased EPA content from the labyrinthulid,   wherein the increased EPA content is not less than 3.3% of a total fatty acid composition.   
     
     
         2 . The method for producing the microbial oil according to  claim 1 ,
 wherein the disrupted and/or silenced gene is a polyketide synthase (PKS) gene, a fatty acid elongase gene and/or a fatty acid desaturase gene,   wherein the transformed another gene is a fatty acid elongase gene and/or a fatty acid desaturase gene.   
     
     
         3 . The method for producing the microbial oil according to  claim 2 ,
 wherein the polyketide synthase (PKS) gene is OrfA,   wherein the fatty acid elongase gene is a C20 elongase gene, and/or   wherein the fatty acid desaturase gene is a Δ4 desaturase gene and/or an ω3 desaturase gene.   
     
     
         4 . The method for producing the microbial oil according to  claim 1 , wherein the genetically modified labyrinthulid is able to grow in media which do not contain PUFA. 
     
     
         5 . The method for producing the microbial oil according to  claim 1 ,
 wherein the step of disrupting or transforming the gene of a labyrinthulid utilizes electroporation or a gene gun method, and/or   wherein the step of silencing the gene utilizes an antisense method or RNA interference.   
     
     
         6 . The method for producing the microbial oil according to  claim 1 , wherein the labyrinthulid belonging to the genus of  Thraustochytrium, Parietichytrium, Schizochytrium , or  Ulkenia.    
     
     
         7 . The method for producing the microbial oil according to  claim 1 , wherein the labyrinthulid is  Thraustochytrium aureum, Thraustochytrium roseum, Parietichytrium sarkarianum, Parietichytrium  sp., or  Schizochytrium  sp. 
     
     
         8 . The method for producing the microbial oil according to  claim 1 , wherein the labyrinthulid is  Thraustochytrium aureum  (ATCC 34304),  Thraustochytrium roseum  (ATCC 28210),  Parietichytrium sarkarianum  SEK364 (FERM BP-11298),  Parietichytrium  sp. SEK358 (FERM BP-11405),  Parietichytrium  sp. SEK571 (FERM BP-11406), or  Schizochytrium  sp. TY12Ab (FERM BP-11421). 
     
     
         9 . A labyrinthulid that has been genetically modified by disrupting and/or silencing a gene, or by transforming another gene in addition to the disruption and/or gene silencing of the gene such that a fatty acid composition accumulated in the labyrinthulid comprises an increased EPA content,
 wherein the increased EPA content is not less than 3.3% of a total fatty acid composition.   
     
     
         10 . The labyrinthulid according to  claim 9 , wherein the disrupted and/or silenced gene is a polyketide synthase (PKS) gene, a fatty acid elongase gene and/or a fatty acid desaturase gene, and wherein the transformed another gene is a fatty acid elongase gene and/or a fatty acid desaturase gene. 
     
     
         11 . The labyrinthulid according to  claim 10 ,
 wherein the polyketide synthase (PKS) gene is OrfA,   wherein the fatty acid elongase gene is a C20 elongase gene, and/or   wherein the fatty acid desaturase gene is a Δ4 desaturase gene and/or an ω3 desaturase gene.   
     
     
         12 . The labyrinthulid according to  claim 9 , wherein the labyrinthulid is able to grow in media which do not contain PUFA. 
     
     
         13 . The labyrinthulid according to  claim 9 , wherein the labyrinthulid belongs to the genus of  Thraustochytrium, Parietichytrium, Schizochytrium , or  Ulkenia.    
     
     
         14 . The labyrinthulid according to  claim 9 , wherein the labyrinthulid is  Thraustochytrium aureum, Thraustochytrium roseum, Parietichytrium  sarkarianum,  Parietichytrium  sp., or  Schizochytrium  sp. 
     
     
         15 . The labyrinthulid according to  claim 9 , wherein the labyrinthulid is  Thraustochytrium aureum  (ATCC 34304),  Thraustochytrium roseum  (ATCC 28210),  Parietichytrium sarkarianum  SEK364 (FERM BP-11298),  Parietichytrium  sp. SEK358 (FERM BP-11405),  Parietichytrium  sp. SEK571 (FERM BP-11406), or  Schizochytrium  sp. TY12Ab (FERM BP-11421).