Produção de biossurfactante por Bacillus Cereus UCP 1615 com potencial para aplicações biotecnológicas industriais

Abstract

The present study characterized and evaluated the biosurfactant produced by Bacillus cereus UCP 1615 in various industrial applications. The production of the biomolecule was carried out in a low-cost medium composed of 2% residual frying soybean oil and 0.12% peptone. The interfacial tension reducing capacity and the critical micelle concentration (CMC) were defined as 6 mN/m and 500 mg/L, respectively. Large-scale production was carried out in 1.2, 3.0 and 50 L bioreactors, reaching surface tension values of 28.7, 27.5 and 32 mN/m and yields around 4.3, 4.6 and 4.1 g/L, respectively. The biosurfactant was classified as an anionic lipopeptide from analyzes to determine ionic charge, thin layer chromatography (TLC), gas chromatography (GC) and nuclear magnetic resonance (NMR). Long-term conservation tests with the additive potassium sorbate (0.2%) demonstrated the stability of the surface-active properties of the biosurfactant, suggesting its application in a possible commercial formulation. To evaluate the application of the biosurfactant in environmental processes, it was applied in tests containing seawater, soil and rocks contaminated with petroleum derivatives and its toxicity was also evaluated against marine organisms Artemia salina (microcrustacean), Poecilia vivipara (fish) and Anomalocardia brasiliana (bivalve) and to the seeds of vegetables Brassica oleracea (cabbage), Solanum lycopersicum (tomato) and Cucumis anguria (gherkin). The biosurfactant proved to be efficient and biocompatible for bioremediation tests in seawater, promoting the growth of the microbiota, and showed removal rates of hydrophobic compounds in sandy soil and rocks of 84 and 69%, respectively. The application of the biomolecule as a bioemulsifier in food was also evaluated through its use in the composition of a cookie type cookie, with cytotoxicity using the L929 and Vero cell lines and the antioxidant activity determined. A biscuit with preserved typical characteristics and benefits compared to the standard without biosurfactant was obtained. Cytotoxicity tests reinforced the biosurfactant's biocompatibility, and the antioxidant activity indicative corroborated with the biosurfactant's contribution to the biscuit preservation. The biosurfactant was also tested as a stabilizer in the synthesis of silver nanoparticles as an antimicrobial agent. Nanoparticles of size around 20 nm were obtained using the green Tollens method. The nanoparticles showed fungicidal activity against human and plant pathogenic fungal genera. The results obtained demonstrate that the biosurfactant from Bacillus cereus UCP 1615 has potential for use in several economic sectors, proving the biotechnological versatility of this biomolecule and its industrial importance.