Biogenesis and Optimisation of Silver Nanoparticles by the Endophytic Fungus Cladosporium sphaerospermum

Abstract

The present study is dealing with an ecofriendly and green biological route for extracellular biosynthesis of silver nanoparticles (AgNPs) using the endophytic fungus Cladosporium sphaerospermum F16 (KU199685). The biosynthesised AgNPs were characterised using ultraviolet-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), dynamic light scattering (DLS), energy-dispersive X-ray analysis (EDX) and X-ray diffraction (XRD). The results showed the formation of stable, well-dispersed and spherical crystalline AgNPs with an average size 15.1 ± 1.0 nm and zeta potential of about −41.2 ± 0.5 mV. Optimisation of AgNPs synthesis prepared under different reaction conditions such as: pH, temperature, silver nitrate concentration and time of synthesis reaction to increase the AgNPs production. Meanwhile, the optimum conditions for maximum AgNPs production were pH (7), silver nitrate (5 mM) and incubation time (5-7 days). Interestingly, the fungal exo-metabolities were found to reduce silver ions into AgNPs within10 min after heating the reaction mixture (50-70 °C) as indicated by the developed reddish brown color compared to 30 min under room temperature.

Applying Taguchi design and large-scale strategy for mycosynthesis of nano-silver from endophytic Trichoderma harzianum SYA.F4 and its application against phytopathogens

“…The results of the nano-Ag as antifungal agent were consisted with few earlier reports293189. The important advantages of Ag NPs-based antimicrobial agents are their biocompatibility, health and environmental safety, and their excellent stability6389 reported that; the mycosynthesized AgN Ps at (5 and 10 ppm) exhibited a more effective activity in inhibiting the mycelia growth of pathogenic strains of Alternaria solani , the causal agent of tomato early blight disease as compared to the recommended chemical fungicide used (Ridomil gold plus 2 g/l).…”

“…These fungal cells was washed extensively using Milli-Q deionized water to remove any medium component and 10.0 g (wet weight) of fungal cells were added to 100 ml distilled water in an Erlenmeyer flask and agitated again at 200 rpm for 48 hr at 30 °C. Then, the cell filtrate (periplasmic fraction) was obtained by filtering through Whatman filter paper2942. The pellet was re-suspended in 5 ml cold 50 mM PBS at pH 7.0 and sonicated on ice with the power level set about 4–5, at 40–50% duty for 15–20 bursts.…”

“…Engineering studies are always interested in consistently producing large quantities of natural bioactive products over long periods of time2829. The best way to achieve this goal will be to grow the cells in a bioreactor where the cellular activity can be controlled efficiently.…”

In vitro and in vivo evaluation of biologically synthesized silver nanoparticles for topical applications: effect of surface coating and loading into hydrogels

“…Cell-free filtrate without AgNO 3 solution was also run as a control. 31 AgNPs dispersion was then centrifuged at 14,000 rpm for 20 min. The supernatant was discarded, and the pellets were redispersed in distilled water, and washed three times with sterilized distilled water to remove the free entities and unbound biological molecules from AgNPs.…”

“…45 Several groups have utilized the crude extract of fungi for myco-synthesis of AgNPs. 31,46,47 Different studies have discussed the fabrication of AgNPs based on fungi-assisted bioreduction processes, as well as their antibacterial activities. 20,48,49 The fungus Fusarium sp.…”