title: Phosphate limitation promotes unsaturated fatty acids and arachidonic acid biosynthesis by microalgae Porphyridium purpureum.
abstract: Polyunsaturated fatty acids (PUFAs) are highly appreciated on their nutritive value for human health and aquaculture. P. purpureum, one of the red microalgae acknowledged as a promising accumulator of ARA, was chosen as the target algae in the present research. Effects of sodium bicarbonate (0.04-1.2 g/L), temperature (25, 30 and 33 °C) and phosphate (0.00-0.14 g/L) on biomass yield, total fatty acids (TFA) and arachidonic acid (ARA) accumulation were investigated systemically. NaHCO3 dose of 0.8 g/L and moderate temperature of 30 °C were preferred. In addition, TFA and ARA production were significantly enhanced by an appropriate concentration of phosphate, and the highest TFA yield of 666.38 mg/L and ARA yield of 159.74 mg/L were obtained at a phosphate concentration of 0.035 g/L. Interestingly, with phosphate concentration continuing to fall, UFA/TFA and ARA/EPA ratios were increased accordingly, suggesting that phosphate limitation promoted unsaturated fatty acids and arachidonic acid biosynthesis. Low concentration of phosphate may be favored to increase the enzymatic activities of ∆6-desaturase, which played a key role in catalyzing the conversion of C16:0 to C18:2, and thus the selectivity of UFA increased. Meanwhile, the increase of ARA selectivity could be attributed to ω6 pathway promotion and ∆17-desaturase activity inhibition with phosphate limitation. Phosphate limitation strategy enhanced unsaturated fatty acids and ARA biosynthesis in P. purpureum, and can be applied in commercial scale manufacturing and commercialization of ARA.
authors.affiliation: College of Energy, Xiamen University, Xiamen, 361005, China.
authors.forename: Gaomin
authors.initials: G
authors.lastname: Su
authors.affiliation: College of Energy, Xiamen University, Xiamen, 361005, China.
authors.forename: Kailin
authors.initials: K
authors.lastname: Jiao
authors.affiliation: College of Energy, Xiamen University, Xiamen, 361005, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Li
authors.affiliation: College of Energy, Xiamen University, Xiamen, 361005, China.
authors.forename: Xiaoyi
authors.initials: X
authors.lastname: Guo
authors.affiliation: College of Energy, Xiamen University, Xiamen, 361005, China.
authors.forename: Jingyu
authors.initials: J
authors.lastname: Chang
authors.affiliation: Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
authors.forename: Theoneste
authors.initials: T
authors.lastname: Ndikubwimana
authors.affiliation: College of Energy, Xiamen University, Xiamen, 361005, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Sun
authors.affiliation: College of Energy, Xiamen University, Xiamen, 361005, China. xianhai.zeng@xmu.edu.cn.|The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, China. xianhai.zeng@xmu.edu.cn.
authors.forename: Xianhai
authors.initials: X
authors.lastname: Zeng
authors.affiliation: Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.|The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, China.
authors.forename: Yinghua
authors.initials: Y
authors.lastname: Lu
authors.affiliation: College of Energy, Xiamen University, Xiamen, 361005, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Lin
mesh_terms: D016718:Arachidonic Acid / Q000096:biosynthesis*; D018533:Biomass; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D044665:Porphyridium / Q000378:metabolism*; D013696:Temperature
chemical_list: D005231:Fatty Acids, Unsaturated; D010710:Phosphates; D016718:Arachidonic Acid
keywords: Arachidonic acid; Phosphate limitation; Porphyridium purpureum; Total fatty acids