Lipases induced by petroleum hydrocarbons [Lipasas inducidas por hidrocarburos del petróleo]

The induction of lipases was evaluated in three hydrocarbonoclastic bacteria (Stenotrophomonas sp., Bacillus sp. and Pseudomonas sp.) by means of five different groups of hydrocarbons (alkenes, gasoline, diesel, kerosene and light petroleum). The lipase monitoring was carried out during 21 days in liquid cultures, containing 24 000 mg of the hydrocarbon/L as the only source of carbon and energy. The results showed that Bacillus sp. presented growth in four of five types of hydrocarbons, but not expressed lipase. Stenotrophomonas sp. and Pseudomonas sp. expressed its capacity of lipase in presence of kerosene and petroleum, and additionally Pseudomonas sp. has lipase activity in presence of n-alkenes and diesel. The enzymatic activity was different depending on the carbon source (kerosene> diesel> petroleum> n-alkenes), the gasoline was not degraded by strains because any of them presented growth. The hydrocarbon concentration was another factor for the expression of the enzyme, showing that Pseudomonas sp. presented a best lipase activity at 90 0000 mg kerosene/L that in the solution of 10 000 mg kerosene/L.

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