Natalia Castejon

1 Introduction Microalgae are photosynthetic eukaryotic microorganisms highly efficient in the fixation of CO2 and using solar energy to produce biomass. They provide a wide range of high-value compounds that are commercially exploited, such as lipids, carotenoids, or proteins [1]. Among these compounds, omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) are the most promising, as microalgae are the primary producers of these essential fatty acids in aquatic systems.

Abstract Polyunsaturated fatty acids (PUFAs) play a crucial role in aiding bacteria to adapt to extreme and stressful environments. While there is a well-established understanding of their production, accrual, and transfer within marine ecosystems, knowledge about terrestrial environments remains limited. Investigation of the intestinal microbiome of earthworms has illuminated the presence of PUFAs presumably of microbial origin, which contrasts with the surrounding soil.

The demand for sustainable and natural food ingredients, driven by increasing consumer interest, has experienced outstanding growth in recent years. In this sense, microalgae have emerged as a highly suitable option for meeting population needs concerning valuable lipids, including omega-3 and omega-6 polyunsaturated fatty acids (n-3 and n-6 PUFA), proteins, and other minor compounds such as carotenoids and chlorophylls.