Biodiesel production from algae can be carried out by different
methods. The most common one is a two-step method in which
algae oil is extracted with organic solvent and then converted to
biodiesel. Also, some authors use the direct extraction-transesterification
of lipids in algae, catalysed by an acid or an enzyme
(10). Tran et al. (10) compared the transesterification of the
extracted microalgal oil and the direct enzyme transesterification
of oil in previously disrupted biomass. Their results show that the
latter procedure achieved higher biodiesel conversion (72.1% and
97.3% wt oil, respectively).
The goal of this work was to produce biodiesel from microalgae
by an alternative two-step enzymatic procedure: (i) extraction of
purified saponifiable lipids (SLs) as FFAs by direct saponification in
the microalgal biomass, and (ii) enzymatic esterification of the
extracted FFAs with methanol. Due to the difficulty of producing
sufficient amounts of microalgal FFAs, the optimization experiments
were carried out with FFAs from used vegetable oil and the
optimal conditions were then applied to FFAs from the microalga
Nannochloropsis gaditana. The findings show that similar results
were attained with both FFAs