1.0 g lyophilized algae biomass was milled and extracted with
20 mL n-hexane with the assistance of pulse sonication at 400 w
for 20 min in an ice-bath, and the resulted supernatant was recovered
after centrifugation at 4250 g for 10 min. The above extraction
process was repeated until the resulted supernatant became colorless.
All resulted supernatants were collected and evaporated in a
rotary evaporator to remove the solvent. The residual crude algal
oil was purified by silica gel column chromatography. n-hexane
was used as the mobile phase solvent. The eluent was collected
in a pre-weighed tube and evaporated in a rotary evaporator. The
residual algal oil was desiccated to a constant weight under nitrogen
flow. The resulted weight was defined as the total algal oil (W1)
in the algal biomass.
For the algal oil extraction experiments from wet algal biomass,
a given amount of wet algal biomass (equal to 0.3 g dry biomass)
was extracted with various solvents in a conical flask with magnetic
stirring (400 rpm, 5 min) at room temperature. The crude extracts
were collected and evaporated in a rotary evaporator to get
the residual crude oil. The resulted crude algal oil was further purified
to obtain the algal oil according to the protocol mentioned
above. The resulted algal oil from the wet algal biomass was
weighed as W2.