Avaliação do potencial nanotecnológico de Aspergillus do bioma Amazônico

Abstract

This study evaluated the potential of Aspergillus strains in the extracellular synthesis of silver nanoparticles with antimicrobial properties. The 20 Aspergillus lines were subcultured in 2% (w/v) glycoside broth at 28 °C for seven days. After monosporic cultivation, the morphological characteristics of Czapek agar, CYA [Czapek Dox agar and 0.5% (w/v) yeast extract] and malt extract agar (MEA) were evaluated for lineage authentication. Molecular identification was performed using rDNA ITS region sequences. The biomass production was done by submerged fermentation in 200 mL of MGYP extract, at 28 ºC, 180 rpm. And as inoculum was added in medium 106 spores/mL medium. After 96 h, in the mycelial extract recovered from the biomass washing AgNO3 solution was added to a final concentration of 1 mM. The synthesis reaction of the silver nanoparticles was performed in the absence of light, at 25 ºC, 180 rpm. The AgNPs were confirmed by UV-vis spectroscopy and the characterization was performed by dynamic light scattering, transmission electron microscopy, X-ray diffraction, X-ray dispersive energy and advanced spectroscopy and spectroscopy methods. Escherichia coli, Staphylococcus aureus, S. epidermidis, Candida albicans and Trichosporon beigelii were the test microorganisms used in the antimicrobial activity of AgNPs by the agar diffusion technique and in the determination of Minimum Inhibitory Concentration (MIC). The membrane was synthesized by electro-spinning and the thickness was analyzed by scanning electron microscopy (SEM). Subsequently, the AgNPs were added to the NanoMAC and the antimicrobial effect was evaluated by the agar diffusion method. The cytotoxicity test was performed against human fibroblasts (MRC5) by the method of Alarmar Blue® using 100 μg/ml of lyophilized AgNPs. The alginate microspheres were synthesized by complex coacervation with incorporation of AgNPs by the in situ and ex situ method and characterized in the SEM. The techniques used in the authentication of Aspergillus were efficient, and the molecular tests classified the strains in the niger and flavus groups. 70% of Aspergillus mediated the synthesis of AgNPs, and the flavus group lineages were more effective. The AgNPs produced were more efficient for yeasts, with CMI for T. beigelii of 0.11 μg/mL and for C. albicans of 0.22 μg/mL, showing no toxicity against the MRC5 lineage. NanoMAC coated with AgNPs showed an increase in antifungal activity of 24.22% when tested against C. albicans. The incorporation of AgNPs into alginate microspheres potentiated the antimicrobial effect of these molecules, especially the anti-yeast effect. Aspergillus isolates from Amazonian biome substrates are promising for use in biological synthesis processes of AgNPs with relevant antimicrobial properties, demonstrating great potential for use in the medical, pharmaceutical and cosmetic fields.