The study of antimicrobial activity of agnps made by using green synthesis against specific microorganisms

Abstract

This work is focused on studying the antimicrobial effect of silver nanoparticles made by green synthesis. For the green synthesis, extracts from Salvia officinalis were used. Four different temperatures (20, 40, 60, 80 °C) were used to prepare the extracts from the plant material. The antimicrobial capability of the AgNPs was assessed using different yeasts (Saccharomyces cerevisiae, Zygosaccharomyces bailii), gram-positive (Lactobacillus plantarum, Listeria innocua, Staphylococcus Aureus) and gram-negative (Escherichia coli, Acetobacter aceti) bacterial strains. The range of AgNPs concentrations 0-2,500 µg/mL were tested. The antimicrobial effect was studied using two methods: 1) the viable cell count method and 2) the inhibition zone method. The method of direct counting showed a small inhibitory effect (inhibition at concentrations 1,250 and 2,500 µg/ml) only for E. coli, Z. bailii and S. cerevisiae. The inhibition zone results displayed better antibacterial activity of the silver nanoparticles (inhibition at all concentrations - 50, 100, 150 and 200 µg/mL) prepared by using the extract obtained at 20 ºC against E. coli and S. aureus.