the SL purities obtained from lyophilized, non-homogenized wet
(control) and homogenized wet biomass at several pressures, all
obtained from biomass of batch 1 after 20 h of extraction. This
table shows that the SL and TL recoveries obtained from lyophi-
lized biomass are higher than those obtained from non-homoge-
nized control, which is logical because the high water content
(86 wt%) hinders the accessibility of hexane to the cells, and also
because lyophilization is a pretreatment that increases the accessi-
bility of hexane to the cells. In any case this difference is small for
SL recovery (0.029 vs. 0.022 g SL/g db) and higher for TL recovery
(0.062 vs. 0.036 g SL/g db), which implies that purity was higher
for the SLs extracted from wet biomass (61.6% vs. 46.4%). This
result seems to indicate that in this microalgal biomass the
absence of water favors more the extraction of unsaponifiable lip-
ids than the extraction of SLs. This purity remains constant (60–
63%) for the SLs extracted from homogenized wet biomass at