Produção, caracterização e aplicação de biossurfactante como agente de remediação em ambiente marinho

Abstract

Contamination by petroleum and its by-products causes serious damage, which has awakened great attention to the development and application of innovative technologies for the removal of these contaminants. In this sense, this work aimed to produce a biosurfactant of Candida tropicalis UCP0996 from industrial residues as substrates for application as a remediation agent. Biosurfactant production optimization was evaluated for the influence of the variables concentrations of molasses, corn steep liquor, residual canola oil and inoculum size on the response variables of surface tension and biosurfactant yield. The optimum conditions selected for the fermentative process were 2.5% of residual canola oil, 2.5% of corn steep liquor, 2.5% of molasses and 2% of inoculum size, with reduction of surface tension and yield of 29.98 mN/m and 4.19 g/L, respectively. The biosurfactant was produced in bioreactors, yielding yields of 5.87 g/L (2 L bioreactor) and 7.36 g/L (50 L bioreactor). The tensioactive and emulsifying capacity of the biosurfactant was investigated under extreme conditions of temperature, salinity, pH and heating time, indicating their stability. Chemical composition investigation of the by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR) and gas chromatography coupled to mass spectrometry (GC-MS) revealed that the biosurfactant studied is an anionic glycolipid with critical micelle concentration (CMC) of 600 mg/L and low hydrophobicity. After the characterization, the biomolecule had its toxicity investigated against the microcrustacean Artemia salina, proving to be innocuous against this environmental indicator. The biosurfactant was then subjected to different methodologies for the formulation of a commercial additive. The biomolecule remained stable for 120 days at room temperature after addition of potassium sorbate as a preservative. The application of the biomolecule in petroderivative removal and degradation processes demonstrated its ability to disperse about 71% of the motor oil into seawater, to remove 67% of the oil adsorbed on a porous surface and to increase the degradation of the oil by microorganisms. Based on the results, it was possible to establish the biotechnological potential of the product obtained for application in the industrial and environmental area, replacing the synthetic surfactants.