T. suecica was cultivated in outdoor bag bioreactors using a modified F medium [16]. Each bioreactor contained up to120L of culture and was aerated with com­pressed air. Temperature and illumination depended on day-to-day weather condi­tions. Microalgal cultures from multiple bioreactors were harvested at the same time (with a concentration of ~0.5 g/L), concentrated via industrial centrifugation, and then mixed together to create a homogeneous culture from which all the bio­mass needed for the study was obtained.

3.2.2 Dewatering

The homogeneous culture was further dewatered in a laboratory centrifuge (Heraeus Multifuge 3S-R, Kendro, Germany) at 4,500 rpm for 10 min. The supernatant was discarded and the resulting microalgal paste was rinsed with deionised water to remove residual salts. The paste was then stored in the dark at either 4 or -20°C until further use.

3.2.3 Extraction Pre-treatment

In experiments where extraction was carried out on dried microalgae, microalgal paste (stored at either 4 or -20°C) was dried at 65°C in an oven (Model UNE 500 PA, Memmert GmbH + Co., Germany) for 16 h. A pestle and mortar was used to grind the dried biomass into powder. In experiments where extraction was carried out on the wet paste, the microalgal paste obtained from centrifugation (stored at 4°C) was used directly. The solid concentration of the paste (22.4 wt.%) was deter­mined by drying a portion of the paste and comparing its pre-dried mass to that of the corresponding dried biomass.