Effective bioprocess engineering to enhance omega-6 polyunsaturated fatty acid production from Arthrospira platensis

Contrary to the robustness of microbial ω-3 polyunsaturated fatty acid (PUFA) production, the microbial synthesis of ω-6 PUFAs remains challenging. The rising demand for ω-6 PUFAs, especially for pregnancy and infant formulas, calls for scalable and sustainable production methods. Arthrospira platensis, a rarely explored microalgae, shows promise as a platform for producing gamma linoleic acid (GLA) and linolenic acid (LA), key components of ω-6 PUFAs. This study employs a two-phase cultivation approach to enhance ω-6 PUFA production in A. platensis. The initial growth phase was optimized to maximize biomass, followed by a stress-induced phase to boost lipid and ω-6 PUFA accumulation. Notably, ω-6 producing strains like A. platensis are protein-rich and not a high oleaginous species, achieving over 15% total lipid content particularly is significant. Under optimized conditions, a maximum biomass of 4.9 g/L with a productivity rate of (0.233 g/L/day) was obtained at 8 K Lux light irradiance, with 2X nitrogen concentration and 4 mg/L phytohormones. The subsequent stress phase, involving 20 K Lux light, 10 mg/L FeSO₄, and 1% glycerol, resulted in a lipid content of 22.8%. This approach led to a 2.4-fold and 1.5-fold increase in microalgal biomass and lipid content respectively. Moreover, C18:2 and C18:3 PUFAs reaching approx. 17.1 ± 0.06% and 24.1 ± 0.07%, respectively. This research promotes microalgae cultivation to meet rising ω-6 PUFA demand, aligning with sustainable development goal 3: Good health and well-being.