The applications of lipase immobilized on ceramic beads and entrapped in sol-gel matrix, in the production of
bio-diesel from waste cooking oil, are compared to that of free lipase. Experimental determination of the effect of molar
equivalent of methanol, to moles of ester bond in the triglyceride, on the rate of the enzymatic trans-esterification was experimentally
determined. It was found that for the same weight of lipase used, the production of bio-diesel was much
higher using lipase immobilized on ceramic beads in comparison to that using lipase entrapped in sol-gel and in free form.
Substrates inhibition effect was observed in all cases, which agrees with previous results found in literature. The optimum
methanol:oil molar ratio was found to be 0.87 for immobilized lipase from yeast source, C. antartica and 1.00 for free lipase
from the same yeast source and immobilized lipase from bacterial source, P. cepacia. On the other hand, it was
shown that biodieasel can be produced in considerable amounts, with yield reaching 40%, in absence of organic solvent
using immobilized lipase, from P. cepacia, on ceramic beads. The results of this study can be used to determine the kinetics
parameters of mathematical models which describe the system.