Partial Purification and Some Biochemical Properties of Lipase from Germinating Oil Palm Seeds

Abstract

Lipases hydrolyze lipids to yield fatty acids and glycerol which are used as raw materials in food, cosmetics and pharmaceutical  industries. This study was conducted to characterize lipase from germinating oil palm seeds. The lipase was extracted, purified and the  biochemical properties were studied. Lipase assay was carried out using p- ntrophenyl palmitate as the substrate. The lipase was  subjected to 80% ammonium sulphate precipitation, purified on ion exchange chromatography column using DEAE Sephadex A50 resin  and gel filteration on Sephadex G-100. Relative molecular weight of the enzyme was determined on a calibrated gel filtration column  using Sephadex G-100 while the subunit molecular weight was estimated on 10% Sodium Dodecyl Sulphate Polycarylamide gel  electrophoresis. Kinetic parameters (K_m and V_max), effect of temperature, pH, and sensitivity to metal ions as well as substrate specificity  of the lipase were studied. The lipase had a specific activity of 27.78 µmol/min/mg, a purification fold of 30.32%. The relative  molecular weight of the enzyme was estimated to be 40kDa, while the K_m and V_max values were 2.5mM and 32.6 µmol/min/ml  respectively. ZnCl₂, KCl, EDTA and MnCl₂, inhibited the enzyme activity, the highest inhibition of 8.53% was observed with EDTA while its  activity was enhanced by CaCl₂. Optimal pH was 7.0 and the temperature for maximal lipase activity was 45^oC. The enzyme hydrolyzed  coconut oil at about twice the rate of palm kernel oil and palm oil, and at a higher rate than olive oil and raphia oil. The study concludes  that germinating oil palm is a good source of lipases which can be of use industrially.