Variation of fatty acid desaturation in response to different nitrate levels in Auxenochlorella pyrenoidosa
Variation of fatty acid desaturation in response to different nitrate levels in Auxenochlorella pyrenoidosa
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蛋白核辅助小球藻中不同硝酸盐水平的脂肪酸去饱和变化
DOI：
10.1098/rsos.181236
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发表时间：
2018-11
影响因子：
3.5
通讯作者：
Xiaoling Miao
中科院分区：
文献类型：
--
作者：
Qi Zhang;Zaizhi You;Xiaoling Miao
微藻是一种很有前途的生物柴油原料，其中高比例的单不饱和脂肪酸如油酸（C18：1）是优选的。为调控微藻的脂肪酸去饱和作用，探讨了硝酸盐浓度、脂肪酸组成与去饱和酶基因表达水平之间的关系。脂肪酸谱的动态变化表明，硝酸盐可以诱导C18脂肪酸去饱和。蛋白核小球藻中C18：1的含量在0 g l−1硝酸盐浓度下为30.88%，而在1.5 g l− 1硝酸盐浓度下为0.48%。进一步研究了Δ 9、Δ12和Δ 15脂肪酸去饱和酶相关基因（Δ9、Δ12和Δ15FADs）的表达。在0 g l−1时，对数期Δ9FAD的表达上调330%，导致C18：1积累。此外，补充硝酸盐导致C18：1从34.79%急剧下降至0.22%，Δ9FAD表达下调至缺乏硝酸盐水平的1%，表明Δ9FAD在C18：1积累中起关键作用。最后，Δ9FAD在大肠杆菌和酿酒酵母中的过表达导致C18：1的增加，证实了其去饱和C18：0的能力。研究结果为利用代谢工程手段提高生物柴油质量和高价值化学品的产业化提供了新的途径和科学指导。
Microalgae are promising feedstocks for biodiesel, where the high proportion of monounsaturated fatty acid such as oleic acid (C18:1) is preferred. To regulate fatty acid desaturation in microalgae, the relationship among nitrate concentration, fatty acid composition and the expression levels of desaturase genes was explored. Dynamic variations of fatty acid profiles suggested nitrate could induce desaturation of C18 fatty acids. The content of C18:1 in Auxenochlorella pyrenoidosa was 30.88% at 0 g l−1 nitrate concentration compared with 0.48% at 1.5 g l−1. The expressions of relative delta-9, 12 and 15 fatty acid desaturase genes (Δ9, Δ12 and Δ15FADs) were further investigated. The 330% upregulated expression of Δ9FAD in logarithmic phase at 0 g l−1 resulted in C18:1 accumulation. Moreover, nitrate replenishment caused a sharp reduction of C18:1 from 34.79% to 0.22% and downregulation of Δ9FAD expression to 1% of the nitrate absence level, indicating the pivotal role of Δ9FAD in C18:1 accumulation. Finally, overexpression of Δ9FAD in Escherichia coli and Saccharomyces cerevisiae resulted in an increase of C18:1, confirming its ability of desaturating C18:0. The results could provide a new approach and scientific guidance for the improvement of biodiesel quality and industrialization of high-valued chemicals by means of metabolic engineering.
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影响因子：
4.1
作者：
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通讯作者：
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影响因子：
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影响因子：
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影响因子：
11.4
作者：
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通讯作者：
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