Nitrogen Deprivation in Fremyella diplosiphon Augments Lipid Production without Affecting Growth
Nitrogen Deprivation in Fremyella diplosiphon Augments Lipid Production without Affecting Growth
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DOI：
10.3390/en13215769
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发表时间：
2020-11
期刊：
影响因子：
3.2
通讯作者：
Behnam Tabatabai;Afua Adusei;A. Shrivastava;P. Singh;V. Sitther
中科院分区：
文献类型：
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作者：
Behnam Tabatabai;Afua Adusei;A. Shrivastava;P. Singh;V. Sitther
代谢产物，如脂和蛋白质产生的蓝藻代表了一个很好的生物质来源，不像大豆和玉米的农业土地使用竞争。鉴于其作为生物柴油生产新材料的潜在用途，我们的目的是探讨培养时间和氮浓度对双倍管弗氏藻，一种模式蓝藻的生长速率和脂质含量的影响。在本研究中，F.将在补充有1.5 g L−1硝酸钠（NaNO 3）的BG 11/HEPES培养基中生长7、10、15和20天的双孢管菌与在补充有0.25、0.5和1.0 g L−1 NaNO 3的培养基中未处理的对照进行比较。将培养物接种在液体培养基中，并在轨道孵育摇床中在连续荧光下生长，并对提取的脂质进行重量分析和气相色谱-质谱分析，以确定脂质生产的最佳培养条件。我们的研究结果表明，氮浓度的降低对所有培养期间的生长速率没有显着影响，但是，总脂含量的积累显着影响氮浓度。在添加1.0 g L−1 NaNO 3的BG 11/HEPES培养基中培养10天后，观察到最大脂质产量（40%），且生长没有减少。酯交换脂质的脂肪酸甲酯组成表明，在所有处理的累积脂质中，棕榈酸甲酯（50-70%）含量较高，其次是十八碳烯酸甲酯（17-30%）。在所有测试样品中还观察到痕量的十二烷酸甲酯、十六烷酸甲酯、十八烷酸甲酯和十八碳二烯酸甲酯（1-8%），表明培养基中的氮剥夺增加脂质产生而不影响生长。
Metabolic products such as lipids and proteins produced in cyanobacteria represent an excellent source of biomass and do not compete with agricultural land use unlike soybean and corn. Given their potential use as novel materials for biodiesel production, we aimed to explore the effect of cultivation period and nitrogen concentration on the growth rate and lipid content of Fremyella diplosiphon, a model cyanobacterium. In this study, F. diplosiphon grown in BG11/HEPES medium supplemented with 1.5 g L−1 sodium nitrate (NaNO3) for 7, 10, 15, and 20 days were compared to the untreated control in media amended with 0.25, 0.5, and 1.0 g L−1 NaNO3. Cultures were inoculated in liquid media and grown under continuous fluorescent light in an orbital incubator shaker, and extracted lipids subjected to gravimetric analysis and gas chromatography-mass spectroscopy to determine the best culture conditions for lipid production. Our results demonstrated that a reduction in nitrogen concentration had no significant effect on the growth rate across all cultivation periods; however, the accumulation of total lipid content was significantly influenced by nitrogen concentration. A maximum lipid production (40%) with no reduction in growth was observed in 10-day old cultures in a BG11/HEPES medium supplemented with 1.0 g L−1 NaNO3. Fatty acid methyl ester composition of transesterified lipids demonstrated high amounts of methyl palmitate (50–70%) followed by methyl octadecenoate (17–30%) in the accumulated lipids at all treatments. Trace quantities of methyl dodecanoate, methyl hexadecanoate, methyl octadecanoate, and methyl octadecadienoate (1–8%) were also observed in all tested samples, indicating that nitrogen deprivation in culture media increases lipid production without affecting growth.