Aplicação de biossurfactantes para dispersão de derramamento de óleo e limpeza de areia

Abstract

The oil industry growth has caused an increase in the number of accidents involving oil spills in coastal and estuarine regions. A striking example was the heavy oil that hit the coast of the Northeast and beaches of Espírito Santo and Rio de Janeiro in 2019, being the largest environmental disaster in extension ever recorded in Brazil. Aiming to contribute for development strategies for bioremediation of oil contaminated environment, the present study evaluated the potential of the biosurfactant produced by a bacterial strain, identified as TIM49, as an oil dispersing agent and cleaning oil-contaminated beach sands. The surfactant activity was proven by determining the emulsification index, surface tension reduction, dispersing activity of oil spilled in water and cleaning oil-contamianted beach sand, using the synthetic surfactant SDS as a reference. The producing species was identified by sequencing the RNAr 16S gene and the surfactant molecule characterized by infrared spectroscopy. Exotoxicity was evaluated against Artemia sp. The biosurfactant produced by TIM49 has emulsifying activity, being able to emulsify a water-kerosene mixture, 62%, as well as to reduce the surface tension of water from 75 mN/m to 27.4 mN/m. It is also an efficient oil dispersant, superior to SDS (sodium dodecyl sulfate), and an excellent sand cleaning agent, removing 98% of impregnated oil, similar to SDS (p> 95%), with the advantages of being biodegradable and non-toxic, as it not caused the death of nauplii of Artemia sp. TIM49, even at a concentration 10 times greater than its critical micellar concentration (11 mg / L). TIM49 was identified as Bacillus subtilis, a species of biosafety level NB-1 and the biosurfactant belongs to the class of lipopeptides, which are recognized as potent surfactants. Therefore, the crude supernatant of the TIM49 culture, rich in biosurfactant, represents an efficient and ecologically compatible alternative to the synthetic surfactants commonly used as a oil dispersant and cleaning agents for beach sand impregnated with oil.