Synthesis of Bioactive Silver Nanoparticles by a Pseudomonas Strain Associated with the Antarctic Psychrophilic Protozoon Euplotes focardii

• Published in: Marine Drugs
• Main Authors: Maria Sindhura John, Joseph Amruthraj Nagoth, Kesava Priyan Ramasamy, Alessio Mancini, Gabriele Giuli, Antonino Natalello, Patrizia Ballarini, Cristina Miceli, Sandra Pucciarelli
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2020
• Subjects: green synthesis biomaterials; silver nitrate; antibiotics; nanotechnology; Biology (General); QH301-705.5; Antarctic; The Antarctic; Antarc*
• Online Access: https://doi.org/10.3390/md18010038; https://doaj.org/article/61e2dea22730469eb80414ea266a524f

The synthesis of silver nanoparticles (AgNPs) by microorganisms recently gained a greater interest due to its potential to produce them in various sizes and morphologies. In this study, for AgNP biosynthesis, we used a new Pseudomonas strain isolated from a consortium associated with the Antarctic marine ciliate Euplotes focardii . After incubation of Pseudomonas cultures with 1 mM of AgNO 3 at 22 °C, we obtained AgNPs within 24 h. Scanning electron (SEM) and transmission electron microscopy (TEM) revealed spherical polydispersed AgNPs in the size range of 20−70 nm. The average size was approximately 50 nm. Energy dispersive X-ray spectroscopy (EDS) showed the presence of a high intensity absorption peak at 3 keV, a distinctive property of nanocrystalline silver products. Fourier transform infrared (FTIR) spectroscopy found the presence of a high amount of AgNP-stabilizing proteins and other secondary metabolites. X-ray diffraction (XRD) revealed a face-centred cubic (fcc) diffraction spectrum with a crystalline nature. A comparative study between the chemically synthesized and Pseudomonas AgNPs revealed a higher antibacterial activity of the latter against common nosocomial pathogen microorganisms, including Escherichia coli, Staphylococcus aureus and Candida albicans . This study reports an efficient, rapid synthesis of stable AgNPs by a new Pseudomonas strain with high antimicrobial activity.