A euryhaline Nannochloropsis gaditana with potential for nutraceutical (EPA) and biodiesel production

The holy grail of the present work was to study the effects of salinity (20, 30, 35, and 40 g/L), light intensity (60 and 150 mu mol photons m(-2) s(-1)) and photoperiod (24 h: 0 h, 18 h: 06 h, 12 h: 12 h, 06 h: 18 h and 00 h: 24 h light: dark) on selective nutraceutical properties of Nannochloropsis gaditana with a focus on eicosapentaenoic acid production. The maximal biomass (45.01 +/- 1.01 mg L-1 day(-1)) and lipid productivities (14.63 +/- 0.79 mg L-1 day(-1)) were obtained at a salinity gradient of 20 g/L, whereas the maximal eicosapentaenoic acid (EPA) productivity was found at 60 mu mol photons m(-2) s(-1) and a photoperiod regime of 18 h: 06 h (light: dark), which yielded high EPA contents of 37.83 +/- 0.37% and 32.16 +/- 0.40%, respectively. Low salinity augmented both the chlorophyll-a and carotenoid contents (11.71 +/- 0.40 and 4.32 +/- 0.15 mu g/mL, respectively) compared with high salinity. The eicosapentaenoic acid (C20: 5) content of the strain was in the range of 19.13 +/- 0.08 to 37.83 +/- 0.37%. Principal component analysis demonstrated a correlation between saturated andmonounsaturated fatty acid synthesis. After significant extraction of long-chain PUFA (EPA and AA), the residual oil can be used for the production of biodiesel that complieswith the European standards for biodiesel. This study investigated the nutrient profile of EPA-enrichedmicroalgae N. gaditana, which can be used for nutraceutical production, and established that the remaining oil (excluding EPA and AA) may be a promising biodiesel feedstock due to its high SFA and MUFA contents. (C) 2015 Elsevier B.V. All rights reserved.