title: Isolation and characterization of polyunsaturated fatty acid producing Thraustochytrium species: screening of strains and optimization of omega-3 production.
abstract: An isolation program targeting Thraustochytrids (marine fungoid protists) from 19 different Atlantic Canadian locations was performed. Sixty-eight isolates were screened for biomass, total fatty acid (TFA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) content. Analysis of fatty acid methyl ester results discerned four distinctive clusters based on fatty acid profiles, with biomass ranging from 0.1 to 2.3 g L(-1), and lipid, EPA, and DHA contents ranging from 27.1 to 321.14, 2.97 to 21.25, and 5.18 to 83.63 mg g(-1) biomass, respectively. ONC-T18, was subsequently chosen for further manipulations. Identified using 18S rRNA gene sequencing techniques as a Thraustochytrium sp., most closely related to Thraustochytrium striatum T91-6, ONC-T18 produced up to 28.0 g L(-1) biomass, 81.7% TFA, 31.4% (w/w biomass) DHA, and 4.6 g L(-1) DHA under optimal fermentation conditions. Furthermore, this strain was found to produce the carotenoids and xanthophylls astaxanthin, zeaxanthin, canthaxanthin, echinenone, and beta-carotene. Given this strain's impressive productivity when compared to commercial strains, such as Schizochytrium sp. SR21 (which has only 50% TFA), coupled with its ability to grow at economical nitrogen and very low salt concentrations (2 g L(-1)), ONC-T18 is seen as an ideal candidate for both scale-up and commercialization.
authors.affiliation: Fermentation and Metabolic Engineering Group, Ocean Nutrition Canada Ltd., 101 Research Drive, Dartmouth, Nova Scotia B2Y 4T6, Canada. aburja@ocean-nutrition.com
authors.forename: Adam M
authors.initials: AM
authors.lastname: Burja
authors.forename: Helia
authors.initials: H
authors.lastname: Radianingtyas
authors.forename: Anthony
authors.initials: A
authors.lastname: Windust
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Barrow
mesh_terms: D001267:Atlantic Ocean; D018533:Biomass; D002170:Canada; D002338:Carotenoids / Q000096:biosynthesis; D004271:DNA, Fungal / Q000737:chemistry / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000737:chemistry / Q000302:isolation & purification; D004281:Docosahexaenoic Acids / Q000378:metabolism; D015118:Eicosapentaenoic Acid / Q000096:biosynthesis; D015525:Fatty Acids, Omega-3 / Q000096:biosynthesis*; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis*; D005658:Fungi / Q000145:classification* / Q000302:isolation & purification / Q000378:metabolism*; D020459:Genes, rRNA / Q000235:genetics; D019015:Geologic Sediments / Q000382:microbiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012331:RNA, Fungal / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D017422:Sequence Analysis, DNA; D024341:Xanthophylls / Q000096:biosynthesis
chemical_list: D004271:DNA, Fungal; D004275:DNA, Ribosomal; D015525:Fatty Acids, Omega-3; D005231:Fatty Acids, Unsaturated; D012331:RNA, Fungal; D012337:RNA, Ribosomal, 18S; D024341:Xanthophylls; D004281:Docosahexaenoic Acids; D002338:Carotenoids; D015118:Eicosapentaenoic Acid