Abstract

A wild strain of Yarrowia lipolytica, identified as LMI 91, was isolated from an oleaginous Brazilian fruit called pequi (Caryocar brasiliense Camb), which is a native species of the Brazilian savannah and which acts as a potent lipase producer. The present study examined the effects of certain factors, such as the combination of casein and meat peptones, as well as the initial pH of a culture medium in lipase produced by Y. lipolytica LMI 91. Experiments were conducted within a low concentration of olive oil, at a temperature of 30°C and a fermentation time of 60 h, under orbital shaking. The response surface methodology was used to determine the optimum concentration of the constituents’ composition. A 2² experimental design with four axial points and three central points was employed in the optimization experiments, and interactive regression analysis was performed to obtain the optimum concentration. The experimental values were found to be in accordance with the predicted values, presenting a correlation coefficient of 0.866. The maximum lipase activity (13.0 U/mL) was obtained by peptone mixture of 70 g/L (1:1) and an initial pH of 5.0.

Key words: Yarrowia lipolytica, wild strain, extracellular lipase, fermentation, optimization.

Abbreviation

 CCRD, Central composite rotatable design; RSM, response surface methodology; SA, Sabouraud agar; X, coded levels of variables; Y, lipase activity (U/mL).