Lipase activity was assayed based on measurement of fatty acids release due to
enzymatic hydrolysis of triglicerides in stabilized emulsion of olive oil (Borlongan,
1990). Assay was carried out by the addition of 1 ml of crude enzyme extract to 1 ml of
stabilized lipase substrate in 1.5 ml of 0.1 M Tris–HCl buffer at pH 8.0. Mixture was
incubated for 6 h at 37 jC, after which hydrolysis was stopped by addition of 3 ml of
95% ethyl alcohol. The mixture was then titrated with 0.01 N NaOH using 0.9% (w/v)
thymolphthalein in ethanol as indicator. Blank determinations were conducted in a
similar manner except that the crude enzyme extracts were introduced into the assay
system after the 6-h incubation and immediately before titration. A unit of lipase activity
(U) was defined as the volume of 0.01 N NaOH required to neutralize the fatty acids
released during the 6-h incubation with the substrate and after correction by the
appropriate blank.