二十碳五烯酸
微绿球藻
叶绿体
生物
脂肪酸
六烯酸
生物化学
食品科学
藻类
植物
多不饱和脂肪酸
基因
作者
Jin Liu,Meijing Liu,Yufang Pan,Ying Shi,Hanhua Hu
标识
DOI:10.1016/j.ymben.2021.11.015
摘要
The marine alga Nannochloropsis oceanica has been considered as a promising photosynthetic cell factory for synthesizing eicosapentaenoic acid (EPA), yet the accumulation of EPA in triacylglycerol (TAG) is restricted to an extreme low level. Poor channeling of EPA to TAG was observed in N. oceanica under TAG induction conditions, likely due to the weak activity of endogenous diacylglycerol acyltransferases (DGATs) on EPA-CoA. Screening over thirty algal DGATs revealed potent enzymes acting on EPA-CoA. Whilst overexpressing endogenous DGATs had no or slight effect on EPA abundance in TAG, introducing selected DGATs with strong activity on EPA-CoA, particularly the Chlamydomonas-derived CrDGTT1, which resided at the outermost membrane of the chloroplast and provided a strong pulling power to divert EPA to TAG for storage and protection, led to drastic increases in EPA abundance in TAG and TAG-derived EPA level in N. oceanica. They were further promoted by additional overexpression of an elongase gene involved in EPA biosynthesis, reaching 5.9- and 12.3-fold greater than the control strain, respectively. Our results together demonstrate the concept of applying combined pulling and pushing strategies to enrich EPA in algal TAG and provide clues for the enrichment of other desired fatty acids in TAG as well.
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