Microwave assisted green synthesis of pectin based silver nanoparticles and their antibacterial and antifungal activities

In this work, monodispersed silver nanoparticles (Ag NPs) were prepared by the reaction of silver nitrate with alkali hydrolyzed pectin at microwave irradiation. Two types of Ag NPs were obtained under the following conditions: 400W of microwave power, 1 g/l NaOH, 2 g/l pectin, 10 mmol/l AgNO3, and irradiation time for 1 and 2 min, respectively. The zeta potential values of Ag NPs colloidal solutions were -39.6 and -38.7 mV, indicating that these nanoparticles were stable. Transmission electron microscopy (TEM) analysis revealed these spherical Ag NPs with an average size 2.90 and 11.94 nm, respectively. Ag NPs exhibited potent antibacterial and antifungal activities to against Escherichia coli, Staphylococcus aureus, and Aspergillus japonicus, and the minimum bactericidal concentrations (MIC) to against E. coli and S. aureus were equally at 80-160 mg/ml. In a word, this is a green, efficient, and cost-effective method for Ag NPs synthesis. (C) 2019 Elsevier B.V. All rights reserved.