An eco-friendly approach to the synthesis of silver nanoparticles (AgNPs) by extracellular components of Streptomyces albogriseolus has been reported. The isolated actinobacteria were genotypically identified by 16S rRNA sequencing analysis, and the morphology was observed by high-resolution scanning electron microscopy. The preliminary characterization of synthesized nanoparticles was carried out using ultraviolet-visible spectrophotometer. The maximum absorption spectra were found to be 409 nm at the 48th hour of incubation. The yield of AgNPs was found to be 72.64% as quantified by an atomic absorption spectrophotometer. The average size of AgNPs determined by the dynamic light scattering technique was 16.25 ± 1.6 nm. The results from transmission electron microscopy and X-ray diffraction confirmed the formation of spherical shaped and crystalline AgNPs. The interaction of protein with AgNPs was confirmed by Fourier transform infrared spectroscopy analysis. The biosynthesized AgNPs inhibited the growth of food pathogens (Bacillus cereus, Escherichia coli, and Staphylococcus aureus). Hence, the synthesis of AgNPs by S. albogriseolus could be employed as a probable antimicrobial agent to eliminate pathogenic microorganisms. This approach employed for the synthesis of nanoparticles paves a path for new biomaterial interfaces, which could be applied in different biomedical fields.

Development of eco-friendly processes for nanosynthesis is gaining importance owing to the widespread application of nanoparticles (NPs). In the present study, we have explained the mechanism and kinetics of bioreduction in the biosynthesis of silver nanoparticles (AgNPs) using aqueous leaf extract of Rhizophora apiculata. Spectrophotometric methods were employed to quantify the bioactive molecules present before and after the reduction process. The results showed that the polyphenols were the main components responsible for the biosynthesis of AgNPs, which was further confirmed by Fourier transform infrared spectroscopy. The kinetics of formation of AgNPs were monitored by time-resolved spectrophotometric and X-ray diffraction studies, which revealed that the NP formation is an autocatalytic process with a rate constant of 1.9 × 10(-2)  Min(-1) . The NPs were characterized using spectroscopic and microscopic techniques like ultraviolet-visible absorption spectroscopy, dynamic light scattering, transmission electron microscopy, scanning electron microscopy-energy-dispersive X-ray spectroscopy, and X-ray diffraction. The biogenic AgNPs showed substantial inhibitory activity to Proteus mirabilis, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus with minimum inhibitory concentration values of 2.5, 12.5, 2.5, and 31.25 μg/mL, respectively. The current research provides an insight into the mechanistic aspects of bioreduction and formation of AgNPs.