Browsing by Author "Eliapenda Elisante Mariki"

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    Commiphora swynnertonii-derived silver nanoparticles significantly enhance the selectivity of the medium for isolating fungal species
    (Springer, 2026-02) Celina Ntibigwahake; Alinanuswe Mwakalesi; Eliapenda Elisante Mariki; Douglas Mushi
    Silver nanoparticles (Ag-NPs) were synthesized using an eco-friendly and economically feasible procedure from the root bark of the medicinal plant Commiphora swynnertonii, with optimized physicochemical variables in the reaction medium. The formation of Ag-NPs was visually monitored by a color change in the reaction mixture and confirmed by various analyses, including UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The synthesized Ag-NPs were tested for their antimicrobial properties and applied to enhance the detection and selective isolation of fungal species on potato dextrose agar (PDA). The optimal synthesis conditions for Ag-NPs were found to be at 60 °C, pH 9, 0.004 M AgNO₃, 40 mL of C. swynnertonii root bark extract, and a reaction time of 10 min. Under these conditions, the Ag-NPs exhibited a maximum absorption peak at 413 nm, spherical shapes, and an average size of 40 ± 15 nm. EDX analysis confirmed the presence of a substantial amount of silver in the synthesized nanoparticles, while FT-IR analysis identified functional groups on their surfaces derived from the root bark of C. swynnertonii. The Ag-NPs demonstrated enhanced antimicrobial activity against Gram-positive and Gram-negative bacteria (MIC, 0.058 mg/mL) compared to filamentous and non-filamentous fungi (MIC, 0.116 mg/mL). PDA without Ag-NPs supported bacterial and fungal growth, whereas PDA with Ag-NPs completely inhibited bacterial outgrowth while permitting fungal outgrowth. This study underscores the potential of C. swynnertonii root bark extract for synthesizing antimicrobial Ag-NPs with applications in controlling pathogenic bacteria and improving the detection sensitivity and selectivity of fungal growth media, particularly PDA.