Characterization of an Extracellular lipase from Yarrowia lipolytica

Lipases from different sources have distinct properties, such as specificity, stability and optimal operational conditions. Moreover, different conditions of lipase production may alter these enzyme properties. Therefore, the aims of this study were related to the evaluation of lipase activity of Yarrowia lipolytica IMUFRJ 50682 (isolated from Baía de Guanabara, Brazil) produced under submerged fermentation, and its characteristics determination. Characterization studies under pH 3-10 (at 37 °C) and temperature 25-55 oC (at pH 7) in the p-nitrophenyl laurate hydrolysis revealed that the enzyme is active in a pH range of 7-9, with a maximum lipase activity at pH 7, and between temperatures of 25-55 oC with an optimum temperature for the lipase activity at 37 oC. The Y. lipolytica enzyme was incubated in dry bath at 25oC, 37oC and 60oC and the residual activities were 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 156.5 h, 106.8 h and 0.058 h at 25oC, 37oC and 60oC, respectively. Regarding storage stability at -10oC, Y. lipolytica lipase was very stable, keeping 100% of residual activity after seven months. Finally, initial rates of hydrolysis were obtained and the Michaelis-Menten constant and Vmax were calculated as 0.234 mM and 0.033 μM/mL/min, respectively.