Avaliação de estratégias para produção e recuperação de vesículas extracelulares de Bacillus sp. C7.1

Abstract

Bacterial extracellular vesicles (EVs) have attracted increasing attention due to their ability to transport active biomolecules, playing roles in communication, environmental adaptation, and potential biotechnological applications. This study aimed to produce and characterize the extracellular vesicles of the Bacillus sp. C7.1 strain under different culture conditions, in order to understand how environmental variables influence their production, morphology, and protein content. The strain was cultivated in Luria Bertani (LB) medium and in medium supplemented with Methyl Orange (MO), a dye previously shown to be degraded by the bacterium in earlier studies. Growth curves, optical density calibration with cell viability (log CFU/mL), protein quantification using BCA assay, morphological analysis via transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA), and protein profiling by SDS-PAGE were performed. Growth curves revealed that MO significantly reduced optical density and accelerated the onset of the stationary phase, suggesting a stress effect. Calibration curves emphasized the importance of correlating OD with cell viability, particularly under stress conditions. Protein quantification indicated relevant differences between treatments, with LB medium promoting higher vesicular protein load. SDS-PAGE analysis revealed distinct protein profiles across treatments, suggesting the existence of vesicle subpopulations with varying functional contents. Decolorization assays using isolated vesicles showed no significant degradation activity against the dye, possibly due to the absence of specific proteins or a lack of appropriate induction conditions. The results indicate that vesicle production in Bacillus sp. C7.1 is sensitive to environmental conditions and that distinct vesicle profiles can be obtained depending on the growth medium. These findings provide a solid foundation for future functional proteomic investigations, aiming at the biotechnological application of these structures, particularly in bioremediation contexts.