CHARACTERIZATION OF AN EXTRACELLULAR LIPASE FROM Yarrowia lipolytica
Integration of life sciences & engineering
Integration of Life Sciences & Engineering - Poster (T5-P)
Keywords: Yarrowia lipolytica, lipase, characterization, p-nitrophenyl laurate
Lipases (EC 3.1.1.3) are enzymes that catalyze the hydrolysis of ester bonds, especially triglycerides with long chains and water-insoluble substrates, and can be found in animals, plants and microorganisms. In organic media, these enzymes catalyze reactions such as esterification, interesterification and transesterification and, therefore, they have become one of the most widely used enzymes in organic synthesis and various industrial applications (detergent, food, oleochemical, pulp and paper industries and resolution of chiral drugs). Lipases from different sources have distinct properties, such as specificity, stability and optimal operational conditions. Moreover, different conditions of lipase production may alter the enzyme properties, for instance, molecular weight, specificity and isoelectric point. Therefore, the aim of this study was to examine the lipase activity of yeast Yarrowia lipolytica IMUFRJ 50682 (Baía de Guanabara isolated strain, Brazil), produced under submerged fermentation, and to determine the characteristics of this enzyme, due to its great importance for different applications as catalysts in a chemical process. The influence of pH, 3-10 (at 37°C) and temperature, 25-55ºC (at pH 7) in the p-nitrophenyl laurate hydrolysis activity was investigated. Moreover, storage stability at -10°C, thermal stability at 25, 37 and 60°C and kinetic parameters of hydrolysis were determined. Best results of enzyme activity were obtained at 37°C and pH 7. The enzyme from Y. lipolytica was incubated in dry bath at 25ºC, 37ºC and 60ºC and the residual activities measured under standard conditions. It became completely inactive after incubation for 15 minutes at 60ºC but was quite stable at 25ºC and 37ºC. The half-lives were 154.37h, 105.34h and 0.058h at 25ºC, 37ºC and 60ºC, respectively. Those results are not very different from the obtained using Candida antarctica lipase B (half-lives of 100.16h and 0.0968h for 37ºC and 60ºC, respectively). Regarding storage stability at -10ºC, Y. lipolytica lipase was very stable, keeping 100% of residual activity after two months of assay. Finally, initial rates of hydrolysis were obtained and used to estimate Km and Vmax, by fitting the Michaelis-Menten model to the experimental data.
See the full pdf manuscript of the abstract.
Presented Wednesday 19, 13:30 to 15:00, in session Integration of Life Sciences & Engineering - Poster (T5-P).
