Characterization of ZnO nanoparticles synthesized using probiotic Lactiplantibacillus plantarum GP258

The fundamental goal of our investigation is to employ a sustainable synthesis method for zinc oxide nanoparticles (ZnO NPs), utilizing lactic acid bacteria isolated from curd as the key biological agent. Bacteria function as agents for both reduction and capping processes, which aids the synthesis of ZnO NPs. Various characterization techniques including XRD, FTIR, UV-vis, TEM, SEM-EDX, and zeta potential measurements were employed to analyze the morphology, dimensions, and elemental composition of the generated nanoparticles. The experimental outcomes confirmed the presence of hexagonal wurtzite-structured ZnO NPs with an average size of 10 nm. The colloidal system demonstrated excellent stability with a zeta potential of -60 mV. Furthermore, the synthesized nanoparticles displayed significant antibacterial activity against selected human pathogens, with the biggest inhibition zone observed against Staphylococcus aureus (22 ± 0.57 mm) and the smallest inhibition zone observed against Salmonella enterica serovar typhi (3 ± 1 mm). MTT assay revealed the promising antiproliferative potential of ZnO NPs, with an average IC₅₀ value of 98.53 µg/mL. Additionally, the NPs were photocatalytically and electrochemically analyzed, indicating their potential use in cancer research as well as in coating and drug delivery applications.