title: Synthesis of silver nanoparticles from two acidophilic strains of Pilimelia columellifera subsp. pallida and their antibacterial activities.
abstract: Biosynthesis of silver nanoparticles (AgNPs) is an eco-friendly approach by using different biological sources; for example, plants and microorganisms such as bacteria, fungi, and actinobacteria. In this report, we present the biological synthesis of silver nanoparticles (AgNPs) by acidophilic actinomycetes SL19 and SL24 strains isolated from pine forest soil (pH < 4.0). The isolates based on 16S rRNA gene sequence were identified as Pilimelia columellifera subsp. pallida. The synthesized AgNPs were characterized by visual observations of colour change from light-yellow to dark-brown. The UV-vis spectra of AgNPs were recorded at 425 and 430 nm. The AgNPs were further characterized by Nanoparticle tracking analysis (NTA), Zeta potential, Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscopy (TEM). FTIR analysis revealed the presence of proteins as a capping agent. TEM analysis confirmed the formation of spherical and polydispersed NPs of 12.7 and 15.9 nm sizes. The in vitro antibacterial activity of AgNPs alone and in combination with antibiotics was evaluated against clinical bacteria viz., Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and uropathogens such as Enterobacter, S. aureus, P. aeruginosa, K. pneumoniae, and E. coli. The lowest MIC (40 μg ml(-1) ) was demonstrated by AgNPs synthesized from SL24 against E. coli. However, the AgNPs of SL19 showed lowest MIC (70 μg ml(-1) ) against S. aureus. The activity of antibiotic was enhanced, when tested in combination with silver nanoparticles synthesized from both actinobacterial strains.
authors.affiliation: Department of Microbiology, Nicolaus Copernicus University, Torun, Poland.
authors.forename: Patrycja
authors.initials: P
authors.lastname: Golińska
authors.affiliation: Department of Microbiology, Nicolaus Copernicus University, Torun, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Wypij
authors.affiliation: Department of Microbiology, Nicolaus Copernicus University, Torun, Poland.|Department of Biotechnology, Nanobiotechnology Laboratory, SGB Amravati University, Amravati, Maharashtra, India.
authors.forename: Dnyaneshwar
authors.initials: D
authors.lastname: Rathod
authors.affiliation: Department of Biotechnology, Nanobiotechnology Laboratory, SGB Amravati University, Amravati, Maharashtra, India.
authors.forename: Sagar
authors.initials: S
authors.lastname: Tikar
authors.affiliation: Department of Microbiology, Nicolaus Copernicus University, Torun, Poland.
authors.forename: Hanna
authors.initials: H
authors.lastname: Dahm
authors.affiliation: Department of Biotechnology, Nanobiotechnology Laboratory, SGB Amravati University, Amravati, Maharashtra, India.
authors.forename: Mahendra
authors.initials: M
authors.lastname: Rai
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000187:drug effects; D001419:Bacteria / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects; D007711:Klebsiella pneumoniae / Q000187:drug effects; D053768:Metal Nanoparticles; D008826:Microbial Sensitivity Tests; D008848:Micromonosporaceae / Q000302:isolation & purification / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012834:Silver / Q000494:pharmacology*; D012988:Soil Microbiology; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D012336:RNA, Ribosomal, 16S; D012834:Silver
keywords: Acidophilic actinobacteria; Biosynthesis; Clinical pathogens; Silver nanoparticles; Uropathogens