title: Delta 5 fatty acid desaturase upregulates the synthesis of polyunsaturated fatty acids in the marine diatom Phaeodactylum tricornutum.
abstract: Microalgae are important primary producers in the marine ecosystem and excellent sources of lipids and other bioactive compounds. The marine diatom Phaeodactylum tricornutum accumulates eicosapentaenoic acid (EPA, 20:5n-3) as its major component of fatty acids. To improve the EPA production, delta 5 desaturase, which plays a role in EPA biosynthetic pathway, was characterized in P. tricornutum. An annotated delta 5 desaturase PtD5b gene was cloned and overexpressed in P. tricornutum. The transgene was integrated into the genome demonstrated by Southern blot, and the overexpression of PtD5b was verified by qPCR and Western blot analysis. Fatty acid composition exhibited a significant increase in the unsaturated fatty acids. Monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) showed an increase of 75% and 64%, respectively. In particular, EPA showed an increase of 58% in engineered microalgae. Meanwhile, neutral lipid content showed an increase up to 65% in engineered microalgae. More importantly, engineered cells showed a similar growth rate with the wild type, thus keeping high biomass productivity. This work provides an effective way to improve the production of microalgal value-added bioproducts by metabolic engineering.
authors.affiliation: Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science and §Department of Food Science, Jinan University , Guangzhou, Guangdong 510632, China.
authors.forename: Kun-Tao
authors.initials: KT
authors.lastname: Peng
authors.forename: Cun-Ni
authors.initials: CN
authors.lastname: Zheng
authors.forename: Jiao
authors.initials: J
authors.lastname: Xue
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Chen
authors.forename: Wei-Dong
authors.initials: WD
authors.lastname: Yang
authors.forename: Jie-Sheng
authors.initials: JS
authors.lastname: Liu
authors.forename: Weibin
authors.initials: W
authors.lastname: Bai
authors.forename: Hong-Ye
authors.initials: HY
authors.lastname: Li
mesh_terms: D053898:Biosynthetic Pathways; D000090943:Delta-5 Fatty Acid Desaturase; D017377:Diatoms / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D044943:Fatty Acid Desaturases / Q000235:genetics / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis* / Q000737:chemistry; D058086:Microalgae / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism
chemical_list: D000090943:Delta-5 Fatty Acid Desaturase; D005231:Fatty Acids, Unsaturated; D044943:Fatty Acid Desaturases