Banca de DEFESA: IVISON AMARO DA SILVA

PRODUCTION OF BIOSURFACTANTS FOR REMEDIATION OF COASTAL ENVIRONMENTAL COMPARTMENTS

 IMPACTED BY PETRODERIVATIVES.

biosurfactants; bioemulsifiers; biotechnology; environmental contamination; petroleum.

The oil spill in the oceans causes irreparable damage to marine life and harms the coastal population of the affected areas. Therefore, the development of spilled oil treatment strategies is essential. Currently, some chemical dispersants have been used in oil spills, although the use of these agents is increasingly restricted due to their toxic potential. In this sense, the present study proposed the production, characterization and application of biosurfactants as adjuvants in the oil contamination processes that impact coastal environments. The production of the biomolecule was tested in 10 different media, being selected the medium 4 containing 1.2% canola oil, 10% commercial sugar, 0.5% millocin, 0.1% K2HPO4, 0.4% of (NH4)2SO4 and 0.05% Mg2SO4.7H2O for the continuity of the tests due to the outstanding results for the ability to reduce surface tension from 72 to 32.762 ± 0.289 mN/m, yield of 23 g/L after isolation with solvents organics and residual motor oil emulsifying capacity of 96.25 ± 0.080%. The critical micellar concentration (CMC) of the biosurfactant produced in medium 4 was 600 mg/L. The behavior of the biosurfactant under extreme conditions of temperature, salinity and pH was evaluated for the parameters of surface tension and emulsifying capacity, where the biosurfactant showed stability without significant loss of its properties. The biosurfactant was classified as a possible sophorolipid based on analysis to determine the ionic charge, thin layer chromatography (TLC), infrared (FT-IR) and nuclear magnetic resonance (NMR). To evaluate the application of the biosurfactant in environmental processes, its toxicity was evaluated against the microcrustacean Artemia salina and its application in tests containing sand through kinetic and static tests and in sea water. The biosurfactant proved to be efficient and biocompatible for the bioremediation of petroleum derivatives, showing removal rates of the hydrophobic compound of 97.8% and 69.2% for the sand remediation processes through kinetic and static tests, respectively. Furthermore, the biosurfactant was able to degrade 91.5% of the contaminant in the seawater test.