The consumption of essential fatty acids, namely omega-3, has been increasingly linked to major health benefits. Currently the main dietary source of these highly valuable fatty acids are small oily fish and their derivatives. Their metabolic capabilities to synthesize these compounds is limited, as is in most vertebrates, and their rich composition derives from biomagnification processes along the marine trophic chains. These originate in microalgae, the primary producers of such high-value polyunsaturated fatty acids (PUFA). As such, understanding the metabolic pathways and lipogenic fluxes of these organisms is extremely relevant particularly if the goal is to optimize and maximize their yields.
Deuterated water (2H2O) has systematically provided reliable lipid biosynthetic flux estimates, validated in several different animal models. The incorporation of deuterium (2 H) into cells follows well-defined metabolic steps and positional 2H-enrichments can be traced by deuterium Nuclear Magnetic Resonance (2 H-NMR). In order to validate its utilization, this study aimed to determine if 2 H-enrichment of the medium interferes with microalgae growth, while assessing the effectiveness of fatty acid 2 H-labelling in microalgae. To achieve this, Munda aquilonaris ACOI 2424 was cultivated in three distinct 2 H concentrations, while growth was monitored through cell counting. Lipids extracted from the resulting biomass were analyzed using NMR, acquiring both 1 H and 2 H spectra. The results showed that 2 H was successfully incorporated into the metabolic pathways enabling the distinction of the de novo omega-3 fatty acid synthesis.
These findings pave the way for innovative metabolic studies using this stable isotope to trace omega-3 lipogenic fluxes in microalgae. This could enhance the production of essential fatty acids and uncover new possibilities for applications in human and animal nutrition.
Supported by Fundação para a Ciência e Tecnologia (FCT; Portugal), co-funded by the European Regional Development Fund (ERDF/FEDER) through the Operational Programme for Competitiveness and Internationalization (POCI/POFC) and structural funds Centre for Functional Ecology UIDB/04004/2020; Associate Laboratory TERRA LA/P/0092/2020.