Green synthesis of antibacterial LFL-ZnO using L. plantarum fermentation liquid assisted by ultrasound-microwave

Green synthesis of antibacterial metal oxide nanoparticles is attractive for develop novel antibacterial agents. In this study, probiotic strain Lactobacillus plantarum ZDY2013 fermentation liquid (LFL) was utilized for the synthesis of zinc oxide nanoparticles (called as LFL-ZnO) via an ultrasound-microwave-facilitated procedure. SEM and TEM show the synthesized LFL-ZnO with a spherical morphology that are surrounded by LFL. Zeta potential and hydrodynamic sizes were - 25.533 +/- 0.205 mV and 537.5 nm by dynamic light scattering (DLS) analyzer, respectively. X-ray diffraction (XRD) results revealed the hexagonal wurtzite structure of LFL-ZnO with a crystallite size of 41 nm. Fourier transform infrared (FTIR) spectrum and thermal gravimetric (TG) curve showed the structure differences between H-ZnO (synthesized by ddH2O instead of LFL) and LFL-ZnO. In addition, LFL-ZnO significantly inhibited the growth of methicillin-resistant Staphylococcus aureus (MRSA) with MIC = 100 mu g/mL. The possible antibacterial mechanisms may be at-tributed to LFL-ZnO release a high concentration of Zn2+ inducing the destruction of bacterial cell integrity resulting in the leakage of protein and reducing sugars. Meanwhile, CLSM results demonstrate the gen-eration of reactive oxygen species (ROS) by LFL-ZnO is another important antibacterial mechanism. The synthesized LFL-ZnO has broad potential to be developed in pharmaceutics as an effective antimicrobial nanomaterial. (c) 2023 Elsevier B.V. All rights reserved.