2.2 Biodiesel production through enzyme-catalyzed transesterification
Around 200 g of oil was weighed to a screw cap Pyrex bottle, with 500 mL of capacity and the bottle
was placed in a thermostatic bath to heat the oil to the reaction temperature. Then, a certain mass of
enzyme was weighted and the ethanol needed was measured in a hood and added to the oil. The
required volume of alcohol was measured and a certain mass of enzyme was weighed, in accordance
with the respective trial, and added to the oil together with a magnetic stir bar. Then, the
transesterification reaction took place for a certain time period in a stirring bath (at 60 rpm) at the
desired temperature depending on the trial conditions. After the reaction ended, the flask was removed
from the bath and the mixture was filtrated to recover the enzyme. The filtrate was placed in a
separating funnel and about 75 g of glycerin (72% purity) was added and left to stand for 15 minutes.
The denser phase (glycerol) was removed from the bottom of the separating funnel to a previously
weighed beaker in order to determine the mass of the recovered crude glycerol.