Enterococcus species for the one-pot biofabrication of gold nanoparticles: Characterization and nanobiotechnological applications

Abstract

In the current work, cell-free extracts of four strains of non-pathogenic Enterococcus species of food origin, were studied for the green synthesis of gold nanoparticles (AuNPs), and characterized by UV–Vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). The AuNPs were evaluated for their Anopheles gambiae larvicidal, dye degradation, antioxidant and thrombolytic activities. The blue-black colloidal AuNPs which absorbed maximally at 549–552nm were nearly spherical in shape, and crystalline in nature with size of 8–50nm. The EDX spectra showed formation of AuNPs to the tune of 89–94%. The prominent FTIR peaks obtained at 3251–3410, 2088 and 1641–1643cm−1 alluded to the fact that proteins were involved in the biofabrication and capping of AuNPs. AuNPs degraded methylene blue and malachite green by 24.3–57.6%, and 88.85–97.36% respectively in 24h, whereas at 12h, larvicidal activities with LC50 of 21.28–42.33μg/ml were obtained. DPPH scavenging activities of 33.24–51.47% were obtained for the biosynthesized AuNPs. The AuNPs prevented coagulation of blood and also achieved 9.4–94.6% lysis of blood clot showing potential nanomedical applications. This study has presented an eco-friendly and economical synthesis of AuNPs by non-pathogenic strains of Enterococcus species for various nanobiotechnological applications.