Extracellular synthesis of silver nanoparticles using entomopathogenic fungus: characterization and antibacterial potential

Abstract

Present study involves the simple, rapid, non-toxic and in vitro method of extracellular silver nanoparticles synthesis using Entomopathogenic fungus (Beauveria bassiana). The development of silver nanoparticle in fungal supernatant was confirmed by the absorbance peak at 450 nm in UV-Vis spectrophotometer. Further, presence of AgNPs and its crystal lattice was confirmed by EDS and XRD, respectively. TEM micrograph confirmed the presence of differently shaped (triangular, circular, hexagonal) nanoparticles with size ranging from 10 to 50 nm. Variable shape and size of fungal assisted AgNps was also confirmed in SEM study. The optimal pH and temperature for biosynthesis of nanoparticles was found to be 6.0 and 25 °C, respectively. The continuous effects of AgNPs against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus in time dependent manner was confirmed in growth kinetic studies. During 36 h of growth study, maximum reduction in O.D 560 was found in E. coli (67.2%) followed by P. aeruginosa (63.3%) and S. aureus (56.8%) at 30 °C. The MIC values of fungal assisted AgNPs against E. coli, P. aeruginosa and S. aureus was found to be 2.5, 3 and 4.5 ppm, respectively. The MIC values of Ciprofloxacin was observed to be 0.5, 0.5 and 0.7 ppm, whereas MICs of AgNPs + Ciprofloxacin showed 0.4, 0.4, 0.5 ppm against E. coli, P. aeruginosa and S. aureus, respectively, clearly highlighting the synergistic effect of AgNPs in combination with Ciprofloxacin. In the view of challenges for developing antimicrobial nanoparticles of variable shape and size by various other methods, tuning nanoparticles synthesis via fungi can be a wonderful approach to resolve existing hurdles.

Synthesis, Characterization, and Optimization of Green Silver Nanoparticles Using Neopestalotiopsis clavispora and Evaluation of Its Antibacterial, Antibiofilm, and Genotoxic Effects

“…The synthesized AgNPs showed an SPR peak observed in the range of 400-450 nm (40). Similarly, the bands were observed in the wavelength of 414 nm, which is typical for AgNPs (Fig 2 ), in agreement with other AgNPs syntheses from biological sources (41)(42)(43)(44)(45)(46).…”

Fusarium oxysporum Silver Nanoparticles; their Characterization and Larvicidal Activity against Aedes Mosquitoes

“…Previously, entomopathogenic fungi such as Beauveria bassiana (Banu and Balasubramanian 2014a; Tyagi et al 2019) (Soni and Prakash 2012b) and F. oxysporum (Vivekanandhan et al 2018a) had been used against Aedes mosquitoes for their larvicidal activities. These entomopathogenic fungi has toxic metabolites cause damage to the cuticle of mosquito larvae (Mannino et al 2019).…”

Biosynthesis of Silver Nanoparticles Mediated by Entomopathogenic Fungi: Antimicrobial Resistance, Nanopesticides, and Toxicity

“…Method of Synthesis The antibacterial application of silver nanoparticles synthesized from entomopathogenic fungi has been focused on bacteria with resistance to drugs such as Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa (Table 1) [54,55]. The effectiveness of these particles in reducing bacterial development is related to the interaction between the characteristics of the nanoparticles (mainly, its size, shape, and surface electrical charge) and bacterial morphological structures.…”

“…The effectiveness of these particles in reducing bacterial development is related to the interaction between the characteristics of the nanoparticles (mainly, its size, shape, and surface electrical charge) and bacterial morphological structures. Electrical charges on the surface of the bacterial cell wall can repel silver nanoparticles, thus reducing their effectiveness [55]. Therefore, these parameters must be carefully evaluated for this type of application.…”