Purification and biochemical properties of lipase from raphia palm fruit mesocarp

Lipases hydrolyze lipids to yield fatty acids and glycerol which are used as raw materials in industries. The lipase from raphia mesocarp was extracted, purified and characterized. Assay was carried out using p- nitrophenyl palmitate as substrate. The lipase was subjected to 80% ammonium sulphate precipitation, purified on ion exchange and gel filtration chromatography. Native and subunit molecular weights were determined on a gel filtration column and 10% sodium dodecyl sulphate polyacrylamide gel electrophoresis respectively. Kinetic parameters (Km and Vmax), effect of temperature, pH, sensitivity to metal ions and substrate specificities of the lipase enzyme were studied. Specific activity of 17.40µmol/min/mg and purification fold of 2.68% were obtained.Native and subunitmolecular weightwas 35 kDa. The Km and Vmax values were0.01mM and 20.5µmol/min/ml respectively. The lipase enzyme was inhibited by all metallic salts used and enhanced by CaCl2. Optimal pH was 7.0 and temperature for maximal activity was 40C. The lipase 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 reveals that raphia mesocarp isa possible source of lipase which can be of industrial use.   Key words: Lipase, raphia palm fruit, mesocarp