Blue-green light is required for a maximized fatty acid unsaturation and pigment concentration in the microalga Acutodesmus obliquus

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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.

Original languageEnglish
Issue number4-5
Pages (from-to)221-232
Number of pages12
Publication statusPublished - 01.07.2022

Bibliographical note

Funding Information:
This study was funded by the research initiative Zukunft Bau of the Federal Institute for Research on Building, Urban Affairs, and Spatial Development (No. SWD- A special thanks goes to Christoph Stegen of the technical support team of the Leuphana University Lüneburg for his excellent technical support and expertise to optimize the experimental setup for microalgae cultivation. We thank Kerstin Nachtigall of the GEOMAR Helmholtz Centre for Ocean Research Kiel, for performing the HPLC-DAD analysis. Finally, we want to thank Professor Dr. Dieter Hanelt, PD Dr. Klaus von Schwartzenberg, and the staff of the Microalgae and Zygnematophyceae Collection Hamburg (MZCH, previously SVCK) microalgae collection of the University of Hamburg for giving us the chance to work with one of their microalgae strains.

Publisher Copyright:
© 2022 The Authors. Lipids published by Wiley Periodicals LLC on behalf of AOCS.

    Research areas

  • blue-green light, fatty acid, lutein, microalgae, photosynthetic pigment
  • Chemistry