Optimization of Pavlova gyrans biomass production and the fatty acid profile using a two-step approach

Abstract

This work aimed to optimize and characterize the biomass production of Pavlova gyrans through a sequential multivariate approach. Among seventeen cultivation parameters, light intensity, NaNO₃, and CuSO₄·5H₂O were identified as the most significative factors (p < 0.10) for biomass productivity. Together with NaH₂PO₄·H₂O, these variables were further studied in order to maximize the biomass production of P. gyrans, with the optimum growth conditions identified as 700 μmol_photons m⁻² s⁻¹ light intensity, 1500 mg L⁻¹ NaNO₃, 6 μg L⁻¹ CuSO₄·5H₂O and 40 mg L⁻¹ NaH₂PO₄·H₂O. These conditions allowed a 3.8-fold increase in biomass production (2.26 g AFDW per L) and improved the biochemical profile (p < 0.05) when compared with the control (Walne's medium). Namely, it was increased the contents of protein (from 10.59 to 30.76% DW), PUFAs (from 37.13 to 47.11% TFA), n − 3 FAs (26.49 to 38.27% TFA), and DHA (from 5.73 to 10.33% TFA). The nutritional value of the microalga (p < 0.05) was also improved, decreasing its atherogenic (AI – from 1.34 to 0.93) and thrombogenic (TI – from 0.45 to 0.24) indices, while the hypocholesterolemic index (HI) increased from 0.96 to 1.63. This work highlights the importance of different growth conditions in P. gyrans, playing a relevant role in the large-scale implementation of this microalga with beneficial nutritional composition for human consumption.