Resumo

Introduction: Biological methods have been reported as alternative to synthesize silver nanoparticles (Ag NP) and recently, we demonstrated the potential of silver nanoparticles (Ag NP) synthesis by fungi isolated from São Paulo State’s (Brazil) mangrove. However, the mechanism of silver nanoparticles (Ag NP) formation by such methods is not established. Objectives: To study the proteins and reductor compounds such as anthraquinones involved in the silver nanoparticles (Ag NP) synthesis. Method: Three fungi coded as L-2-2, R-2BI-4 and MGE-201 were cultivated in Potato Dextrose Broth at 28°C, 150 rpm for 72 h. The biomass was filtered and incubated at the same conditions with water (0.1 g mL-1). The silver nanoparticles (Ag NP) was obtained dissolving 1 mM silver nitrate (AgNO3) into the fungal filtrate (FF) and the suspensions kept in the dark at 25ºC. The protein portion present in the FF and adhered to silver nanoparticles (Ag NP) was analyzed by SDS-PAGE electrophoresis. Extractions liquid-liquid, using organic solvents, were performed to obtain the anthraquinones from the FF, which were analyzed by gas-chromatography–mass spectrometry (GC-MS). Results: Proteins with bands in the range from 25 to 328 kDa was present in the FF and around the silver nanoparticles (Ag NP) and anthraquinones such as chrysophanic acid was detected in the FF by GC-MS. Discussion and Conclusions: Proteins in the range from 25 to 328 KDa were present in the FF and in the silver nanoparticles (Ag NP) indicating their participation in the silver nanoparticles (Ag NP) synthesis. Chrysophanic acid was detected in the FF, but the data are not enough to suggest it contribution in the silver nanoparticles (Ag NP) synthesis. Additional studies are necessary to elucidate the silver nanoparticles (Ag NP) mechanism of formation. Supported by: FAPESP, CNPq and CAPES.