Kinetic characterization of digestive lipase for the hydrolysis of olive and sunflower oils

This paper investigates the hydrolytic activity of digestive lipase (mixture of fungal lipases ofRhizopus oryzae and Aspergillus niger) on olive oil/water and sunflower oil/water emulsions underdifferent reaction conditions such as temperature, pH, incubation time and substrate concentrations.The optimum lipase activity based on free fatty acid production capacity was observed at oilconcentration of 100 mg.mL-1, temperature 45 ℃, pH=7 and 30 min incubation time. Using theLineweaver-Burk plots, Michaelis-Menten rate constants were determined at 82.1 and 53.1mg.mL-1 for emulsions of olive and sunflower oils, respectively. Maximum reaction rates werefound at 1.3 and 1.1 μmol free fatty acids (FFAs).min-1.mL-1 for olive and sunflower oils,respectively. Lipase showed its optimum activity at pH=7-8 and a temperature range between 40and 55℃ for the hydrolysis of both oils. Maximum FFA production was found at30.0-33.1 μmol.mL-1 during 60-70 min of reaction at 45 ℃ and pH=7. In the current study, thespecific lipase activities were determined at 43.3 and 36.7 U.mg-1 for sunflower and olive oils,respectively. The combination of Rhizopus oryzae and Aspergillus niger lipases allowed the highstability to pH and temperature.

کلیدواژه ها:

Lipase ، Olive oil ، Sunflower oil ، Free fatty acid ، Activity ، Hydrolysis