The induction of the lipolytic system through the use of some hydrocarbons as the only carbon source for the growth of Pseudomonas sp. was investigated. The results showed induction of the enzymatic activity using 4 of 11 hydrocarbons used at a concentration of 3,000 mg/L (butylbenzene, 1,2,3,4-tetrahydronaphthalene, hexane and benzene), which suggests that the enzymatic expression is a function of the hydrocarbon used. Furthermore, when the concentration of these hydrocarbons was increased to 5,000 mg/L the enzymatic activity was not detected. Additionally, the effect of an external source of energy, such as sucrose, and the effect of surfactant Triton X-100 were determined. The results revealed that the presence of these may benefit the induction of the enzyme or may affect it negatively and suppress it depending of the hydrocarbon being used. Therefore, it is not feasible to consider the enzymatic activity of lipase as a biomarker in the degradation of all petroleum hydrocarbons.