Oil and eicosapentaenoic acid production by the diatom Phaeodactylum tricornutum cultivated outdoors in Green Wall Panel (GWP®) reactors

Phaeodactylum tricornutum is a widely studied diatom and has been proposed as a source of oil and polyunsaturated fatty acids (PUFA), particularly eicosapentaenoic acid (EPA). Recent studies indicate that lipid accumulation occurs under nutritional stress. Aim of this research was to determine how changes in nitrogen availability affect productivity, oil yield, and fatty acid (FA) composition of P. tricornutum UTEX 640. After preliminary laboratory trials, outdoor experiments were carried out in 40-L GWP (R) reactors under different nitrogen regimes in batch. Nitrogen replete cultures achieved the highest productivity of biomass (about 18gm(-2)d(-1)) and EPA (about 0.35gm(-2)d(-1)), whereas nitrogen-starved cultures achieved the highest FA productivity (about 2.6gm(-2)d(-1)). The annual potential yield of P. tricornutum grown outdoors in GWP (R) reactors is 730kg of EPA per hectare under nutrient-replete conditions and 5,800kg of FA per hectare under nitrogen starvation.