• P-ISSN 0974-6846 E-ISSN 0974-5645

Indian Journal of Science and Technology


Indian Journal of Science and Technology

Year: 2020, Volume: 13, Issue: 31, Pages: 3128-3140

Original Article

Extracellular fabrication of bio-nanostructures from Ralstonia sp. strain NS-7: Characterizations and their microbiological evaluation

Received Date:21 April 2020, Accepted Date:09 June 2020, Published Date:27 August 2020


Objectives: In this study, we took advantage of nanotechnology to systematically investigate the antimicrobial activity of silver nanoparticles (AgNPs) against pathogenic microorganisms. This study aimed to synthesize AgNPs from Ralstonia sp. strain NS-7 and further characterization of synthesized AgNPs. Materials: The molecular characterization of isolated strain Ralstonia sp. NS-7 was done by 16S rRNA gene sequencing and the characterizations of synthesized AgNPs was achieved by UV-Visible spectroscopy, AFM, FTIR, HRTEM, SEM, EDS and XRD. Later on, the efficacy of previously synthesized AgNPs was assessed in vitro against pathogens, such as Escherichia coli, Enterococcus faecalis, Streptococcus pneumoniae and Staphylococcus aureus. Finding: The UVvisible spectrophotometric observation of synthesized AgNPs showed maximum absorbance at 420 nm, the AFM data revealed the polydispersity of spherical nanoparticles. Further, the FTIR analysis expressed a unique IR spectral band patterning and the HR-TEM and SEM analysis showed the size of biosynthesized AgNPs in the range of 14.72 nm to 47.32 nm. The analysis of phylogenetic tree of the strain NS-7 revealed the most sequence similarity with Ralstonia sp. strain PGNP6. Finally, the AgNPs represented a broad-spectrum antimicrobial activity against gram-positive and gram-negative bacteria. Application:The biological method for the synthesis of AgNPs is eco-friendly, economical, green and non-toxic. Synthesized AgNPs from Ralstonia sp. strain NS-7 could be used as an alternative source of antimicrobial for the management of pathogenic and multi-drug resistant microorganisms.

Keywords: Ralstonia sp.; FTIR; HR-TEM; 16S rRNA gene sequencing; antimicrobial activity; AgNPs


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© 2020 Nayaka et al.This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Published By Indian Society for Education and Environment (iSee).


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