Isolation of lipid-rich marine microalgae by flow cytometric screening with Nile Red staining
- 29 Downloads
Microalgae provide an optimal lipid source for commercial applications. The development a rapid, easy, and efficient screening procedure to isolate lipid-rich microalgae is becoming an extraordinarily active field of study. An automated flow cytometric cell-sorting technique in combination with Nile Red (NR) staining was used to isolate lipid-rich microalgae strains from a field sample. Cell sorting was based on the two-dimensional distribution of chlorophyll autofluorescence against forward scatter and NR fluorescence at 576 nm against that at 620 nm, corresponding to the optimal emission wavelength of NR in neutral and in polar lipid fractions, respectively. Of the 24 strains isolated using this method, 13 marine microalgae strains were successfully grown in culture medium and characterized for biomass production and cellular content of neutral and polar lipids based on NR fluorescence after 12 days of cultivation. The production of neutral lipids was higher in two strains (strains 9 and 12) compared to the marine diatom Phaeodactylum tricornutum, which is well known for its high lipid productivity. Three strains (strains 7, 8, and 9) exhibited a higher productivity of polar lipids than observed for P. tricornutum. These results indicate that our proposed method, an automated isolation technique coupled with the use of a specific cell stain such as NR, is efficient for selecting and isolating lipid-rich microalgae strains from the natural environment.
KeywordsCell sorting Flow cytometry Marine microalgae Neutral lipid Polar lipid
We thank Beckman Coulter Inc. for the experimental assistance. Dr. S. Shimode of Yokohama National University helped to collect the algal samples.
This research was supported by the Japan Science and Technology Agency (JST)/Japan International Cooperation Agency (JICA), the Science and Technology Research Partnership for Sustainable Development (SATREPS) through the project for the Continuous Operation System for Microalgae Production Optimized for Sustainable Tropical Aquaculture (COSMOS), and the SATREPS-COSMOS Matching Fund from the Ministry of Higher Education Malaysia (MOHE).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
This article does not contain any studies with animals performed by any of the authors.