Labyrinthulid microorganism capable of producing microbial oil, microbial oil, methods for producing said microorganism and for producing said microbial oil, and uses of said microorganism and said microbial oil
A method for producing a microbial oil includes 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, and 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 labyrinthulid before the modification is selected from (A) a labyrinthulid belonging to the genus Parietichytrium or genus Schizochytrium and having very weak or no activity of producing PUFAs via a PUFA-PKS pathway; and (B) a labyrinthulid belonging to the genus Thraustochytrium in which a host PUFA-PKS gene is disrupted or silenced to a very weak level. The increased EPA content is preferably not less than 11.5% of a total fatty acid composition.
1. A method for producing a microbial oil, comprising:
genetically modifying a labyrinthulid by disrupting and/or silencing a fatty acid desaturase gene;
culturing the labyrinthulid; and
collecting the microbial oil from the labyrinthulid,
wherein the labyrinthulid before the modification belongs to the genus Parietichytrium or the genus Schizochytrium having an activity of synthesizing DHA via a PUFA-PKS pathway in an amount of not more than 1/100 of a total amount of DHA synthesized in the labyrinthulid or no activity of producing PUFAs via the PUFA-PKS pathway, and having an activity of producing PUFAs via an endogenous elongase-desaturase pathway,
wherein the fatty acid desaturase gene is a Δ4 desaturase gene,
wherein the microbial oil satisfies (a) and (b):
(a) DHA is not greater than 0.50% of the total fatty acid composition; and
(b) a total of DHA and n-6 DPA is not greater than 0.7% of the total fatty acid composition.
2. The method for producing microbial oil according to claim 1 ,
wherein the step of disrupting the gene of the labyrinthulid utilizes electroporation, a gene gun method, or gene editing, and/or wherein the step of gene silencing of a labyrinthulid utilizes an antisense method or RNA interference.
3. The method for producing microbial oil according to claim 1 , wherein the labyrinthulid belonging to the genus Parietichytrium is Parietichytrium sarkarianum , and/or wherein the labyrinthulid belonging to the genus Schizochytrium is Schizochytrium aggregatum.
4. The method for producing microbial oil according to claim 1 ,
wherein the labyrinthulid belonging to the genus Parietichytrium is Parietichytrium sp. SEK358 (FERM BP-11405), Parietichytrium sarkarianum SEK364 (FERM BP-11298), or Parietichytrium sp. SEK571 (FERM BP11406), and/or wherein the labyrinthulid belonging to the genus Schizochytrium is Schizochytrium aggregatum ATCC 28209.