Department of Biology and Biotechnology, Worcester Polytechnic Institute, 100 Institute Rd., Worcester, MA 01609, USA.
Appl Microbiol Biotechnol. 2013 Mar;97(5):2263-73. doi: 10.1007/s00253-012-4671-2. Epub 2013 Jan 20.
Temperature and light intensity effects on biomass and lipid production were investigated in Ettlia oleoabundans to better understand some fundamental properties of this potentially useful but poorly studied microalgal species. E. oleoabundans entered dormant state at 5 °C, showed growth at 10 °C, and when exposed to light at 70 μmol photons per square meter per second at 10 °C, cells reached a biomass concentration of >2.0 g L(-1) with fatty acid methyl esters of 11.5 mg L(-1). Highest biomass productivity was at 15 °C and 25 °C regardless of light intensity, and accumulation of intracellular lipids was stimulated by nitrate depletion under these conditions. Although growth was inhibited at 35 °C, at 130 μmol photons per square meter per second lipid content reached 10.37 mg L(-1) with fatty acid content more favorable to biodiesel dominating; this occurred without nitrate depletion. In a two-phase temperature shift experiment at two nitrate levels, cells were shifted after 21 days at 15 °C to 35 °C for 8 days. Although after the shift growth continued, lipid productivity per cell was less than that in the 35 °C cultures, again without nitrate depletion. This study showed that E. oleoabundans grows well at low temperature and light intensity, and high temperature can be a useful trigger for lipid accumulation independent of nitrate depletion. This will prove useful for improving our knowledge about lipid production in this and other oleaginous algae for modifying yield and quality of algal lipids being considered for biodiesel production.
温度和光照强度对埃氏油囊藻生物质和脂类生产的影响，以更好地了解这种具有潜在应用价值但研究甚少的微藻的一些基本特性。埃氏油囊藻在 5°C 时进入休眠状态，在 10°C 时生长，当在 10°C 时暴露于 70 μmol 光子/平方米/秒的光照下时，细胞达到 >2.0 g/L 的生物质浓度，脂肪酸甲酯为 11.5 mg/L。在 15°C 和 25°C 时，无论光照强度如何，最高生物质生产力，在这些条件下，硝酸盐耗尽会刺激细胞内脂类的积累。尽管在 35°C 时生长受到抑制，但在 130 μmol 光子/平方米/秒时，脂质含量达到 10.37 mg/L，脂肪酸含量更有利于生物柴油的主导；这是在没有硝酸盐耗尽的情况下发生的。在两个硝酸盐水平的两相温度转换实验中，细胞在 15°C 下培养 21 天后转移到 35°C 培养 8 天。尽管转移后细胞继续生长，但每个细胞的脂类生产力低于 35°C 培养物，同样没有硝酸盐耗尽。本研究表明，埃氏油囊藻在低温和低光照强度下生长良好，高温可以作为一种有用的触发因素，在不耗尽硝酸盐的情况下促进脂类积累。这将有助于提高我们对这种和其他油脂藻类中脂类生产的认识，以便修改用于生物柴油生产的藻类脂类的产量和质量。
