Vitamin D3, Vitamin K and Fatty Acid Profiles of Nannochloropsis oceanica Grown Under Outdoor Industrial Conditions

Nannochloropsis oceanica is cultivated, at industrial scale, mainly for aquaculture feed and is known to contain different bioactive compounds, such as fat-soluble vitamins and long-chain polyunsaturated fatty acids. However, data on the variability and availability of these compounds over year-long outdoor cultivation conditions are absent. We conducted a longitudinal observational assessment of vitamin D3 and fatty acid content and composition of N. oceanica cultivated in an outdoor pilot scale pond in southern Israel (29.6° N). Cultivation cycles of 30 days were monitored across eight months between January and October. We further determined the vitamin K content during January and March. In freeze-dried biomass the vitamin D3 content ranged from 3 to 253 ng/gram and was positively associated with mean UV-index and pond pH. Menaquinone-4 was the only vitamin K vitamer detected (14–37 µg/gram) and was primarily associated with pond temperature. Total fatty acid in freeze-dried biomass was relatively constant at 7.6 ± 1.7% of which 1–3.5% was eicosapentaenoic acid (EPA). The fatty acid profile shifted during the 30-day cultivation period, with increasing relative proportions of EPA and decreasing proportion of saturated fatty acids. The results highlight substantial temporal and cultivation-related variability under real production conditions and provide a basis for controlled optimization studies.