Produção de biossurfactante por Candida Bombicola e aplicação em solos contaminados por derivado de petróleo.

Abstract

Increasing environmental contamination has significantly impacted ecosystems. In response to this problem, environmental preservation initiatives and current legislation have driven the development of more sustainable alternatives, such as natural products to replace petroleum derivatives. In this context, biosurfactants are natural detergents that emerge as a promising alternative to replace conventional petroleum-derived products. In this context, biosurfactants are natural detergents that emerge as a promising alternative to replace conventional petroleum-derived products. Faced with this situation, the main objective of this study was to generate biosurfactant through Candida bombicola, using industrial waste aiming at sustainable production. as well as investigating the processes of removing petroleum derivatives from soils. For this, a mineral medium composed of NH4NO3 (0,1%), KH2PO4 (0,02%), MgSO4.7H2O (0,02%), supplemented with 6.0% residue from the vegetable oil industry and 1% glutamic acid. The results indicated that the biosurfactant produced reduced the surface tension of the production medium from 50 mN/m to 30 mN/m, with a yield of 2 g/L in a period of 72 hours of fermentation. The critical micellar concentration (CMC) of the biosurfactant was 0.03%, and genotoxicity tests demonstrated no adverse effects on onion roots (Allium cepa). Infrared spectroscopy and magnetic resonance analyzes corroborated the observation of the nature of the product obtained. Surface tension stability tests of the raw biosurfactant were conducted under different conditions, including pH variations (2, 4, 6, 8 and 10), salinity concentrations (2%, 4%, 6%, 8% and 10%), temperatures (5°C, 70°C, 100°C and 120°C), and exposure times at 90°C (10, 20, 30, 40, 50, 60 and 120 minutes). The results demonstrated that the biosurfactant maintained its stability under these varied conditions. Furthermore, the emulsification index after 24 hours (IE24) revealed that the biosurfactant was capable of forming emulsions of up to 95% with burnt engine oil and up to 60% with soybean oil. To evaluate the effectiveness of the biosurfactant in removing engine oil from different types of soil (sandy, silty and clayey), static and dynamic tests were carried out with different concentrations of the biosurfactant (CMC, ½ CMC and 2xCMC). In the static test, the highest percentage of removal was observed in sandy soil, reaching 65.32% removal. In the dynamic test, the highest percentage of removal was 95.60%, using the biosurfactant at a concentration of 2xCMC in both tests. These results highlight the viability and effectiveness of the biosurfactant produced, suggesting its practical application in the environmental recovery of areas contaminated by petroleum derivatives.