Benign nano-assemblages of silver induced by β galactosidase with augmented antimicrobial and industrial dye...

The fabrication of nanoparticles (NPs) has been a wide realm of studies focusing majorly on their dispersion and stabilization. The use of biological components as reducing agents has led to emergence of environment-friendly and cost-effective approaches of synthesis. The primary aim was synthesizing silver nanoparticles (AgNPs) mediated by enzyme β galactosidase. The surface plasmon resonance peaks of AgNPs were screened using ultraviolet-visible spectroscopy against varying time of synthesis and concentration of enzyme. The mean dimension was 12.89 ± 0.16 nm as determined by the transmission electron microscopy and selected area electron diffraction patterns. The obtained NPs were fine spherical and quasi-spherical assemblages as revealed by the scanning electron microscopy studies. Fourier transform infrared spectroscopy confirmed that β galactosidase contributed to the reduction and stabilization of the silver nanoparticles. The crystallinity and presence of elemental silver was displayed by X-ray diffraction and electron dispersive spectroscopy. The antimicrobial efficacy of these AgNPs was tested against the pathogenic bacterial strains of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Staphylococcus epidermidis. The minimum inhibitory concentration, minimum bactericidal concentration and biofilm inhibitory activities were reported depicting enzymatically reduced AgNPs possess an excellent bactericidal activity. An alternative approach was formulated in dye wastewater treatment where the nano-assemblages were reduced within the dye solutions leading to significant decolorization of industrially important dyes; direct, reactive and acid. The cytotoxic potential of the AgNPs was evaluated on peripheral blood lymphocytes in vitro and scanning electron microscope images obtained concluded that green synthesis fabricates benign NPs at low concentrations.