Synthesis of nano silver particles using extracellular polysaccharide of Pseudoduganella armeniaca ZMN-3: antibacterial activity, antibacterial mechanism and antibacterial application as coating.

The present study focused on the antibacterial activity, mechanism and application of Pseudoduganella armeniaca ZMN - 3 extracellular polysaccharide nano silver. Extracellular polysaccharide nano silver was prepared by chemical synthesis and characterized by UV - Vis spectroscopy, Fourier transform infrared spectroscopy, X - ray diffraction, X - ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The antibacterial effects of extracellular polysaccharide nano silver on two common pathogens were investigated by agar well diffusion method and broth dilution method. The results showed that extracellular polysaccharide nano silver had significant inhibitory effects on Escherichia coli and Staphylococcus aureus. In addition, by SEM and TEM observation, the conductivity, the leakage of nucleic acids and proteins, the release of reducing sugars, the ATP content, and the alkaline phosphatase level were also measured. The study results indicated that extracellular polysaccharide nano silver could cause the leakage of large biomolecules such as nucleic acids and proteins, reduce the release of sugars, increase ATP content, and lead to the leakage of alkaline phosphatase, ultimately resulting in bacterial death. Finally, the application of extracellular polysaccharide nano silver in antibacterial coating was studied. Antibacterial coating achieved an impressive inhibition rate of 99% against both Escherichia coli and Staphylococcus aureus and could effectively resist bacterial adhesion within 7 days. This study provides a theoretical basis for the potential application of Pseudoduganella armeniaca ZMN - 3 extracellular polysaccharide nano silver in the antibacterial field.