Green Synthesis of Silver Nanoparticles Using a Biosurfactant from Bacillus cereus UCP 1615 as Stabilizing Agent and Its Application as an Antifungal Agent

Abstract

Silver nanoparticles have great potential in a wide range of applications. Therefore, the purpose of this work was to synthesize, in a simple and green way, via the Tollens method, silver nanoparticles (AgNPs), using as a stabilizer the biosurfactant produced by Bacillus cereus UCP 1615 cultivated in a low-cost medium, with waste frying oil as a substrate. The obtained nanoparticles were identified and morphologically characterized using ultraviolet/visible (UV/vis) spectroscopy, scanning electron microscopy (SEM), and zeta potential. The maximum UV/vis absorption was observed at 400 nm for newly formed silver nanoparticles, while, for silver nanoparticles stored for 120 days, the peak was observed at 430 nm. SEM micrographs confirmed the formation of nanoparticles, with predominantly spherical structures. The average size of the formed nanoparticles was estimated to be 20 nm. The presence of the biosurfactant promoted stability, as a zeta potential of −23.4 mV was observed. The antimicrobial potential of AgNPs was evaluated at different concentrations against three pathogenic fungi (Aspergillus niger, Penicillium fellutanum, and Cladosporium cladosporioides). No less than 100% and 85% inhibitions of P. fellutanum and A. niger growth were observed, respectively, at the AgNP concentration of 16.50 µg/mL in potato dextrose agar medium. These results suggest the potential use of the biosurfactant as a stabilizer for silver nanoparticles and its application as an antimicrobial agent.

Role of surface‐active materials (amphiphiles and surfactants) in the formation of nanocolloidal dispersions, and their applications

“…The obtained spherical nanoparticles (20 nm in size) were characterized using UV/vis spectroscopy, scanning electron microscopy (SEM), and zeta potential measurements. The presence of the bio‐surfactant promoted stability; zeta potential of was observed (Durval et al, 2021). Magnesium hydroxide () is important in paper industry, and ultrathin nanoflakes of () was prepared with high‐dispersion stability via a simple one‐step surfactant (CTAB) assisted strategy (Wang et al, 2022).…”

Advances in stabilization of metallic nanoparticle with biosurfactants- a review on current trends

“…Rhamnolipid, a biosurfactant prepared from residues of refining vegetable oils and 2.5 % corn steep liquor, was found to be nontoxic and biodegradable. Durval et al [ 158 ] synthesized silver nanoparticles (AgNPs) in an environmentally friendly manner by using a biosurfactant produced by Bacillus cereus UCP 1615 as a stabilizer. The diameter of the generated nanoparticles was determined to be about 20 nm.…”

Antimicrobial mechanism and biocontrol effect of Bacillus cereus XZ30-2 on Aspergillus niger

“…Meanwhile, the diameter of the oil drainage circle was 7.35 cm if 20-μL culture filtrate was added to the media, indicating the presence of surfactin in the culture filtrate (Figure 6D). Similarly, antimicrobial substances produced by B. cereus had an inhibitory effect and could be taken as antifungal agents (Durval et al, 2021;Ming et al, 2022).…”