Microalgal powder (20 g) or paste (8 g) was mixed with inert
diatomaceous earth (d.e.) at specific ratios (powder: d.e. =
2:1 w/w and paste: d.e. = 1:2 w/w). The addition of d.e. or celites
(diameter = 3–5 lm, specific surface area = 30720 cm2/cm3) as an
anchoring co-matrix enhanced contact surface area between the
microalgal cells and the eluting supercritical fluid. The resulting
homogeneous mixture was tightly packed into the extraction vessel
and the vessel was sealed with metal frits at both ends to avoid
entrainment of the microalgal biomass. Once the vessel was placed
in the oven, the extraction unit was operated as previously
described.