Freshwater green alga Chlorella sp. KLSc59 produced all forms of omega-3 oil: ALA, EPA, and DHA

Abstract

Omega-3 fats are known to be the essential nutrient for human health, obtainable only through food sources. Algae and phytoplankton are primary sources that can synthesize various useful metabolites, such as carotenoids, antioxidants, and omega-3 oil. As the trend toward healthy alternative food options grows, this study aimed to screen eight strains of freshwater microalgae that might be promising sources of omega-3 oil. The results showed that three algal strains-BNG2, Chlorella sp. KLSc59, and Chlorella sp. KLSc61-had the ability to produce all forms of omega-3 oil, including alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Among these strains, Chlorella sp. KLSc59 exhibited the most consistent omega-3 fatty acids-production when detected with gas chromatography equipped with flame ionization detector. Under optimal conditions (30 % flask volume, 10 mM CaCl2, pH of 6.0, and light incubation at 162 μmol photons m−2 s−1) for 5 days, Chlorella sp. KLSc59 produced the highest amount of omega-3 fat, yielding 21.74 ± 0.63 % of the total peak area (equivalent to 18.43 ± 0.6 μg/mg DCW), including 21.53 ± 0.66 % (equivalent to 18.26 ± 0.7 μg/mg DCW) ALA, 0.03 ± 0.2 % (equivalent to 0.02 ± 0.0 μg/mg DCW) EPA, and 0.18 ± 0.01 % (equivalent to 0.15 ± 0.0 μg/mg DCW) DHA, with an omega-6 to omega-3 ratio of 2.28. This study highlights the potential use of Chlorella sp. KLSc59 for omega-3 oil production and its role as an alternative source of omega-3 oil for the next generation.