Can microalgal omega-3 PUFA production systems remain viable as GM plant sources emerge?

The global market for omega-3 polyunsaturated fatty acids (ω3-PUFA) is valued at ∼$2.8 billion and growing but production of fish oil, the main source of this ω3-PUFA demand, is static and expected to decline. Photosynthetic microalgae, which use light and CO₂ to produce ω3-PUFA are classified vegan, are typically able to grow rapidly in seawater using controlled systems and are in many cases enriched in DHA and/or EPA, yielding sustainable, vegan ω3-PUFA production. Findings from the literature show that microalgal systems achieve higher areal productivity and require less land than crop-based systems (5x more biomass per unit land area than terrestrial crop plants and higher oil yield), but face persistent challenges related to higher energy demand, contamination risks, and limited economic feasibility. GM oilseeds may deliver lower costs at scale (due to established infrastructure and farming subsidies) but lack the product diversity, rapid production cycles, and circular bioeconomy potential of microalgae. We examine advances in cultivation strategies, trophic modes, and metabolic engineering that could enhance yields and reduce costs in microalgal production systems. In particular, pathway engineering, strain robustness, and integration of biorefinery approaches are central to future cost reduction. Addressing energy-intensive downstream processing and contamination management will also be critical to commercial success. Finally, we assess the GM plants as competitors to microalgal sources of, highlight their respective strengths and weaknesses, and outline likely production landscapes for ω3-PUFAs over the next decades.