Pavlova gyrans as a potential source of essential fatty acids, sterols and pigments: culture under low temperature

Abstract

Haptophytes are emerging as sustainable sources of high-value metabolites such as polyunsaturated fatty acids (PUFAs). The goal of this work was to isolate a native haptophyte from the southwestern Atlantic coast and to evaluate the effect of low-temperature stress on the concentration of PUFAs, sterols, and pigments during its cultivation. The strain was identified as Pavlova gyrans. Cultures were carried out in a photobioreactor for 10 days at 20 °C (Control), lowering the culture temperature to 10 °C at the beginning of the stationary growth phase (LTS). The lipid content of the biomass represented 13% of the dry weight, neutral lipids being the main lipid fraction. Under LTS, biomass increased significantly, reaching a value of 305 mg L−1. The same effect was observed with PUFAs content, which represented 41.3% of total fatty acids. The most abundant omega-3 (ω3) and omega-6 (ω6) fatty acids were eicosapentaenoic (EPA) and docosapentaenoic (DPA), respectively. PUFAs concentration under LTS reached 6.65 mg L−1 of which 3.59 mg L−1 corresponded to ω3 and 3.06 mg L−1 to ω6. EPA reached a value of 2.82 mg L−1 while that for DPA was of 1.59 mg L−1. The maximum content of phytosterols was obtained during the exponential growth phase. The most abundant phytosterol was 24-ethylcholesta-5,22-dien-3β-ol, which represented ≈41–49% of the free sterol fraction, with a volumetric concentration of ≈320 μg L−1. Finally, under LTS pigments reached a value of ≈700 μg L−1. These results open the way for further progress towards the commercial and profitable cultivation of P. gyrans for food and aquaculture applications.