Blue-green light is known to maximize the degree of fatty acid (FA) unsaturation in microalgae. However, knowledge on the particular waveband responsible for this stimulation of FA desaturation and its impact on the pigment composition in microalgae remains limited. In this study, Acutodesmus obliquus was cultivated for 96 h at 15°C with different light spectra (380–700 nm, 470–700 nm, 520–700 nm, 600–700 nm, and dark controls). Growth was monitored daily, and qualitative characterization of the microalgal FA composition was achieved via gas chromatography coupled with electron impact ionization mass spectrometry (GC-EI/MS). Additionally, a quantitative analysis of microalgal pigments was performed using high-performance liquid chromatography with diode array detection (HPLC-DAD). Spectra that included wavelengths between 470 and 520 nm led to a significantly higher percentage of the polyunsaturated fatty acids (PUFA) 18:3 and 16:4, compared to all other light conditions. However, no significant differences between the red light cultivations and the heterotrophic dark controls were observed for the FA 18:3 and 16:4. These results indicate, that exclusively the blue-green light waveband between 470 and 520 nm is responsible for a maximized FA unsaturation in A. obliquus. Furthermore, the growth and production of pigments were impaired if blue-green light (380–520 nm) was absent in the light spectrum. This knowledge can contribute to achieving a suitable microalgal pigment and FA composition for industrial purposes and must be considered in spectrally selective microalgae cultivation systems.

中文翻译：

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蓝绿光是微藻 Acutodesmus obliquus 中脂肪酸不饱和度和色素浓度最大化所必需的

众所周知，蓝绿色光可以最大限度地提高微藻中的脂肪酸 (FA) 不饱和度。然而，关于导致这种 FA 去饱和刺激的特定波段及其对微藻中色素组成的影响的知识仍然有限。在本研究中，Acutodesmus obliquus在 15°C 下以不同的光谱（380-700 nm、470-700 nm、520-700 nm、600-700 nm 和暗对照）培养 96 小时。每天监测生长，并通过气相色谱结合电子碰撞电离质谱 (GC-EI/MS) 对微藻 FA 组成进行定性表征。此外，使用具有二极管阵列检测的高效液相色谱法 (HPLC-DAD) 对微藻色素进行了定量分析。与所有其他光照条件相比，包含 470 至 520 nm 波长的光谱导致多不饱和脂肪酸 (PUFA) 18:3 和 16:4 的百分比显着提高。然而，对于 FA 18:3 和 16:4，在红光培养和异养暗对照之间没有观察到显着差异。这些结果表明，A. 斜角。此外，如果光谱中没有蓝绿光（380-520 nm），色素的生长和生产就会受到损害。这些知识有助于获得适合工业用途的微藻色素和 FA 组合物，并且必须在光谱选择性微藻培养系统中加以考虑。