Green Synthesis and Antimicrobial Activities of Silver Nanoparticles using Cell Free-Extracts of Enterococcus species

Abstract

Cell-free extracts of six strains of Enterococcus species obtained from fermented foods were used for the green synthesis of silver nanoparticles (AgNPs), which was characterized by UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The biosynthesized AgNPs were dark brown in colour having surface plasmon resonance in the range of 420-442 nm. The spherical shaped AgNPs had sizes of 4-55 nm, whose formations were facilitated by proteins as indicated by the presence of peaks 1,635-1,637 and 3,275-3,313 cm-1 in the FTIR spectra. The energy dispersive x-ray (EDX) showed prominent presence of silver in the AgNPs colloidal solution, while the selected area electron diffraction was typified by the face-centred crystalline nature of silver. The particles inhibited the growth of multi-drug resistant clinical isolates of Escherichia coli, Klebsiella pneumoniae and Proteus vulgaris, and also potentiated the activities of ampicillin, ciprofloxacin and cefuroxime in the AgNPs-antibiotic synergy studies. In addition, the prospective relevance of the particles as nanopreservative in paints was demonstrated with the inhibition of growth of Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus niger and A. flavus in AgNPs-paint admixture. This report further demonstrates the green synthesis of AgNPs by strains of Enterococcus species.

Silver‐gold alloy nanoparticles biofabricated by fungal xylanases exhibited potent biomedical and catalytic activities

“…Consequently, there arose a demand for green nanotechnology that comprises clean, safe, and environmentally friendly systems of nanoparticles fabrication. 2 The biological technique, which is a key component of the green nanotechnology has expanded in the last decade to biosynthesize metallic nanoparticles owing to abundance of a wide-range of biological resources such as bacteria, [3][4][5][6][7] fungi, 8 plants' extracts, [9][10][11][12][13][14] enzymes, [15][16][17][18][19][20][21] as well as metabolites of arthropods. [22][23][24][25][26][27][28][29] There are outstanding reviews on the use of pigments, agrowastes, enzymes, arthropods, and their metabolites for the ecofriendly and benign synthesis of nanoparticles.…”

Anti-pathogenic efficacy of biogenic silver nanoparticles through adherence and biofilm inhibition in multidrug resistant ESKAPE pathogens

“…The formation of AgNPs in an aqueous medium was confirmed by the UV-visible spectra and the maximum colour intensity was attained after 12 hrs. The change in colour was due to reduction of silver ion by the biomolecules and enzymes present in the cell-free extracts [28]. The presences of free electrons in silver nanoparticles are responsible to raise absorption band with the combined vibration of electrons of metal nanoparticles [29].…”

Comparative Effects of Silver Nanoparticles, Sucrose and Sodium Chloride as Osmotic Solutions for Tomato Slices: Antioxidant Activity, Microbial Quality and Modelling with Polynomial Regression Model

“…Furthermore, the AgNPs demonstrated larvicidal activities against larvae of Anopheles gambiae, and also prevented coagulation of blood. 28,[30][31][32]…”

“…Though there is dearth of information on the toxicity of AgNPs from food consumption but concerns about the potential toxicity likely due to release of silver ion (Ag + ) exist. [28][29][30][31][32][33][34][35][36]54,55 However, results of Yekeen et al 56 show that AgNPs has minimal effects on the inhibition of Allium cepa cells. Consequently, a comparative study with biogenic silver nanoparticles (AgNPs) synthesized from extracts of cocoa beans (CBE) as an alternative to constantly used osmotic solutions was undertaken in this study.…”