The results obtained in this study revealed
that after the pre-treatment (esterification), the high FFA level
from 10.8% was reduced to 0.59%. Previous studies reported that
the microalga Microcystis aeruginosa contained high levels of FFA
(11.7%) in the lipids which was reduced to less than 1% using acid
esterification reaction [48]. Tiwari et al. [49] also reported that acid
esterification (1.43% H2SO4 v/v) reduced the FFA content in lipids
from 14% to less than 1% in Jatropha oil.