Savant spd111 speedvac

Lipid contents of microalgae were analyzed using a method adapted from Bligh and Dyer [52 (link)]. Briefly, 200 mg of the freeze-dried biomass were weighed accurately into 15 mL centrifuge polypropylene tubes and were supplemented by 800 µL MilliQ water, 2 mL chloroform, and 1 mL methanol. The mixture was vigorously stirred for 120 s. Thereafter, additional 2 mL of chloroform and 2 mL MilliQ water were added followed by stirring for another 120 s. The suspension was then centrifuged at 8,000 × g for 10 min. The lower organic phase containing extracted lipids was recovered and transferred into tubes previously dried and weighed, while the remaining aqueous phase and also the biomass residues were re-extracted with 2 mL of chloroform for two more times [53 (link)]. The chloroform phases were combined together, and the solvent was evaporated in a centrifugal evaporator Speed-Vac (Savant™ SPD111 SpeedVac™, Thermoscientific) at 40°C under a vacuum of 950 mbar, up to weight stabilization. This pellet is resuspended in 200 μL chloroform (for fatty acid analysis). The percentage of the lipid content was determined using Equation ((Eq. (10)):Lipid content%=Weight of lipidmgWeight of dried microalgae biomassmg×100