Bacteriogenic synthesis of morphologically diverse silver nanoparticles and their assessment for methyl orange dye removal and antimicrobial activity.

Nanotechnology and nanoparticles have gained massive attention in the scientific community in recent years due to their valuable properties. Among various AgNPs synthesis methods, microbial approaches offer distinct advantages in terms of cost-effectiveness, biocompatibility, and eco-friendliness. In the present research work, investigators have synthesized three different types of silver nanoparticles (AgNPs), namely AgNPs-K, AgNPs-M, and AgNPs-E, by using Klebsiella pneumoniae (MBC34), Micrococcus luteus (MBC23), and Enterobacter aerogenes (MBX6), respectively. The morphological, chemical, and elemental features of the synthesized AgNPs were analyzed by using UV-Vis spectroscopy (UV-Vis), Fourier transform-infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and energy-dispersive spectroscopy (EDX). UV-Vis absorbance peaks were obtained at 475, 428, and 503 nm for AgNPs-K, AgNPs-M, and AgNPs-E, respectively. The XRD analysis confirmed the crystalline nature of the synthesized AgNPs, having peaks at 26.2°, 32.1°, and 47.2°. At the same time, the FTIR showed bands at 599, 963, 1,693, 2,299, 2,891, and 3,780 cm-1 for all the types of AgNPs indicating the presence of bacterial biomolecules with the developed AgNPs. The size and morphology of the AgNPs varied from 10 nm to several microns and exhibited spherical to porous sheets-like structures. The percentage of Ag varied from 37.8% (wt.%) to 61.6%, i.e., highest in AgNPs-K and lowest in AgNPs-M. Furthermore, the synthesized AgNPs exhibited potential for environmental remediation, with AgNPs-M exhibiting the highest removal efficiency (19.24% at 120 min) for methyl orange dye in simulated wastewater. Further, all three types of AgNPs were evaluated for the removal of methyl orange dye from the simulated wastewater, where the highest dye removal percentage was 19.24% at 120 min by AgNPs-M. Antibacterial potential of the synthesized AgNPs assessment against both Gram-positive (GPB) Bacillus subtilis (MBC23), B. cereus (MBC24), and Gram-negative bacteria Enterococcus faecalis (MBP13) revealed promising results, with AgNPs-M, exhibiting the largest zone of inhibition (12 mm) against GPB B. megaterium. Such investigation exhibits the potential of the bacteria for the synthesis of AgNPs with diverse morphology and potential applications in environmental remediation and antibacterial therapy-based synthesis of AgNPs.

Phytonanofabrication of iron oxide particles from the Acacia jacquemontii plant and their potential application for the removal of brilliant green and Congo red dye from wastewater.

Phytonanofabrication is one of the most promising areas that has drawn the attention of scientists worldwide due to its eco-friendly nature and biocompatibility. In the current investigation, we reported the phyto-assisted formation of iron oxide nanoparticles (IONPs) from a rare species of Acacia (Acacia jacquemontii). First, ethanolic extracts of the stem powder were analyzed by high-performance thin-layer chromatography (HPTLC) for the identification of phytochemicals in the stem sections of Acacia. Furthermore, IONPs were synthesized by a chemical co-precipitation method by using the stem extract. The phytonanofabricated iron oxide particles were investigated by UV-Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Energy-dispersive X-ray spectroscopy (EDS) for elemental analysis. HPTLC confirmed the presence of several phenols and terpenoids in the ethanolic extracts of the stem. UV-Vis spectroscopy exhibited an absorbance peak at 380 nm, indicating the formation of IONPs, while FTIR spectroscopy showed the typical bands for Fe-O in the range of 599-1,000 cm-1 in addition to several functional groups of organic molecules at 1,596 cm-1, 2,313 cm-1, and 3,573 cm-1. XRD exhibits the amorphous nature of IONPs with peaks at 30.7, 35.5, and 62.7 nm. The IONPs were spherical-shaped, whose size varies from 10 to 70 nm, as confirmed by FESEM. EDS exhibited the presence of Fe, O, C, and NaCl. Finally, the phytonanofabricated iron oxide particles were utilized for the removal of brilliant green (BG) and Congo red (CR) dye from the aqueous solution. The removal efficiency of BG dye was up to 54.28%, while that of Congo red dye was up to 36.72% in 120 min and 60 min, respectively. Furthermore, the effect of pH and contact time was also assessed on both the dyes, where CR exhibited maximum removal at acidic pH, i.e., 47.5%, while BG showed maximum removal at pH 10, i.e., 76.59%.