The importance of
n-3 long chain polyunsaturated fatty acids (LC-PUFAs) for human health has received more focus the last decades, and the global consumption of
n-3 LC-PUFA has increased. Seafood, the natural
n-3 LC-PUFA source, is harvested beyond a sustainable
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The importance of
n-3 long chain polyunsaturated fatty acids (LC-PUFAs) for human health has received more focus the last decades, and the global consumption of
n-3 LC-PUFA has increased. Seafood, the natural
n-3 LC-PUFA source, is harvested beyond a sustainable capacity, and it is therefore imperative to develop alternative
n-3 LC-PUFA sources for both eicosapentaenoic acid (EPA, 20:5
n-3) and docosahexaenoic acid (DHA, 22:6
n-3). Genera of algae such as
Nannochloropsis,
Schizochytrium,
Isochrysis and
Phaedactylum within the kingdom Chromista have received attention due to their ability to produce
n-3 LC-PUFAs. Knowledge of LC-PUFA synthesis and its regulation in algae at the molecular level is fragmentary and represents a bottleneck for attempts to enhance the
n-3 LC-PUFA levels for industrial production. In the present review,
Phaeodactylum tricornutum has been used to exemplify the synthesis and compartmentalization of
n-3 LC-PUFAs. Based on recent transcriptome data a co-expression network of 106 genes involved in lipid metabolism has been created. Together with recent molecular biological and metabolic studies, a model pathway for
n-3 LC-PUFA synthesis in
P. tricornutum has been proposed, and is compared to industrialized species of Chromista. Limitations of the
n-3 LC-PUFA synthesis by enzymes such as thioesterases, elongases, acyl-CoA synthetases and acyltransferases are discussed and metabolic bottlenecks are hypothesized such as the supply of the acetyl-CoA and NADPH. A future industrialization will depend on optimization of chemical compositions and increased biomass production, which can be achieved by exploitation of the physiological potential, by selective breeding and by genetic engineering.
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