Actinomycetes-mediated biogenic synthesis of metal nanoparticles and their antimicrobial activities are well documented. Actinomycetes facilitate both intracellular and extracellular metal nanoparticles synthesis and are efficient candidates for the production of polydispersed, stable and ultra-small size metal nanoparticles. Secondary metabolites and new chemical entities derived from Actinomycetes have not been extensively studied for the synthesis of metal/metal oxide nanoparticles. The present review focuses on biogenic synthesis of metal nanoparticles from Actinomycetes and the scope for exploring Actinomycetes-derived compounds (enzymes, organics acids and bioactive compounds) as metal and metal oxide reducing agents for the synthesis of desired nanoparticles. This review also focuses on challenges faced in the applications of nanoparticles and the methods to synthesize biogenic metal nanoparticles with desired physiochemical properties such as ultra-small size, large surface to mass ratio, high reactivity etc. Methods to evade their toxicity and unique interactions with biological systems to improve their chance as an alternative therapeutic agent in medical and pharmaceutical industry are also discussed. © 2017 The Society for Applied Microbiology

Kannabiran K

Department of Bio-Medical Sciences

School of Bio Sciences and Technology

Vellore Campus

Manimaran M

Fulltext

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

&nbsp;

&nbsp;

VIT University

Letters in Applied Microbiology

Objectives: The aim of the present study was to evaluate the anticandidal activity of biologically synthesized silver nanoparticles using the culture filtrate of Streptomyces sp.VITPK1. Materials and methods: Silver nanoparticles were synthesized using the culture filtrate of Streptomyces species isolated from brine spring located at Thoubal District, Manipur, India. The isolate was identified by molecular taxonomic characterization and designated as Streptomyces sp.VITPK1. The synthesized silver nanoparticles (AgNPs) were characterized by UV-visible spectra, X-ray diffraction (XRD) patterns, Energy Dispersive Analysis of X-rays (EDAX) and Fourier Transform Infrared (FTIR) analysis. The antifungal activity of the synthesized silver nanoparticles was evaluated against selected Candida species. Results: The synthesized AgNPs showed a surface plasmon resonance peak at 425. nm. XRD patterns showed the crystalline peaks at 38.15° (111), 44.35° (200), 64.52° (220) and 77.49° (311) matching with the diffraction facets of silver. The size of the AgNPs was in the range of 20-45. nm. The EDAX analysis revealed the presence of silver as the major metal in the sample. The synthesized AgNPs showed anticandidal activity against Candida albicans, Candida tropicalis and Candida krusei with a maximum zone of inhibition of 20. mm against C.albicans. Conclusions: The results of this study suggest that the green synthesis of silver nanoparticles using Streptomyces sp.VITPK1 have the ability to act against pathogenic Candida strains. © 2014 Elsevier Masson SAS.

Journal de Mycologie Médicale

Anticandidal activity of silver nanoparticles synthesized using Streptomyces sp.VITPK1

Emergence of antibiotic resistance by bacteria has become a serious threat for public health worldwide. In this study, Streptomyces isolated from fertile soil sample was tested for biosynthesis of silver nanoparticles (AgNps) using cell-free supernatant and synthesized AgNps were screened for anti-ESBL (extended spectrum b-lactamase) activity against multi-drug resistant (MDR) ESBL-producing strain Klebsiella pneumoniae (ATCC 700603) and other medically important pathogens. Synthesis of AgNps was confirmed by change in pale yellow color to dark brown color and characteristic absorption spectra at 420 nm. The XRD spectrum displayed typical peaks of crystalline silver and EDAX analysis showed a major signal for silver. FTIR spectra revealed prominent peaks at 3,294 cm-1 (NH stretching due to amide group), 2,952 cm-1 (aldehydic C-H stretching) 1,658 cm-1 indicating the presence of carbonyl group. AgNps were spherical in shape with size ranging from 20 to 70 nm. The synthesized AgNps showed significant antimicrobial activity against standard ESBL pathogen K. pneumoniae (22 mm), 21 mm against clinical ESBL isolate E. coli and 16 mm against clinical ESBL isolates K. pneumoniae and Citrobacter species, respectively. The results of this study suggest that AgNps synthesized by Streptomyces sp. VITSJK10 can be used as a potential alternative to control MDR ESBL pathogens. The present study aimed for green synthesis of AgNps using Streptomyces species and to explore its anti-ESBL activity. © Springer-Verlag 2013.

Bioprocess and Biosystems Engineering

Anti-ESBL activity of silver nanoparticles biosynthesized using soil Streptomyces species

In the present study, the marine actinobacteria mediated biosynthesis of silver nanoparticles (AgNps) was achieved using Streptomyces sp LK3. The synthesized AgNps showed the characteristic absorption spectra in UV-vis at 420 nm, which confirmed the presence of nanoparticles. XRD analysis showed intense peaks at 2θ values of 27.51, 31.87, 45.57, 56.56, 66.26, and 75.25 corresponding to (210), (113), (124), (240), (226), and (300) Bragg's reflection based on the fcc structure of AgNps. The FTIR spectra exhibited prominent peaks at 3,417 cm-1 (OH stretching due to alcoholic group) and 1,578 cm-1 (C=C ring stretching). TEM micrograph showed that the synthesized AgNps were spherical in shape with an average size of 5 nm. Surface morphology and topographical structure of the synthesized AgNps were dignified by AFM. The synthesized AgNps showed significant acaricidal activity against Rhipicephalus microplus and Haemaphysalis bispinosa with LC50 values of 16.10 and 16.45 mg/L, respectively. Our results clearly indicate that AgNps could provide a safer alternative to conventional acaricidal agents in the form of a topical antiparasitic formulation. The present study aimed to develop a novel, cost-effective, eco-friendly actinobacteria mediated synthesis of AgNps and its antiparasitic activity. © 2013 Springer-Verlag Berlin Heidelberg.

Streptomyces sp. LK3 mediated synthesis of silver nanoparticles and its biomedical application

Objective: The aim of the present study was to assess the anti-Aspergillus activity of culture filtrate of Streptomyces sp. VITSTK7 and biologically synthesized Ag2O/Ag nanoparticles using the culture filtrate of VITSTK7. Material and methods: Silver nanoparticles were synthesized by biological reduction of silver nitrate using culture filtrate of Streptomyces sp. VITSTK7. The synthesized nanopaticles were characterized for surface plasma resonance peak, X-ray diffraction patterns, shape and size distribution. Inhibition of mycelial growth was used as an index of anti- Aspergillus activity of synthesized nanoparticles. Results: The synthesized nanoparticles were spherical shaped and monodespersive in nature and showed a single surface plasma resonance peak at 420. nm. X-ray diffraction patterns displayed typical peaks of crystalline silver oxide and size distribution histograms indicated production of 20-60-nm-size nanoparticles with average size of 35.2. nm. The synthesized nanoparticles showed anti- Aspergillus activity against Aspergillus niger, Aspergillus flavus and Aspergillus fumigatus with antifungal index in the range of 62-75%. Conclusion: Thus the bioconversion of Ag2O/Ag nanoparticles by Streptomyces sp. VITSTK7 could be employed to control Aspergillus pathogenesis. The results of this study suggest that the green synthesis of Ag2O/Ag nanoparticles using marine Streptomyces sp. VITSTK7 yielded 27.9nm sized particles with potential to act against pathogenic Aspergillus species. © 2013 Elsevier Masson SAS.

Antifungal activity of Streptomyces sp . VITSTK7 and its synthesized Ag 2 O/Ag nanoparticles against medically important Aspergillus pathogens

The conventional method of synthesizing gold nanoparticles (Au NPs) by chemical methods tends to cause an environmental concern; therefore there is an increasing tendency to use safe and nontoxic methods. The aim of the present study was to evaluate the anti-dermatophytic potential of biologically synthesized Au NPs using the cell free supernatant of Streptomyces sp. VITDDK3. The synthesized Au NPs were characterized using UV-visible spectra at 550 nm. XRD pattern analysis revealed peaks at 38.10° (111), 44.28° (200), 64.42° (220) and 77.37° (311) corresponding to the diffraction facets of Au. SEM analysis showed that the Au NPs were cubical in shape with an average size of 90 nm. The synthesized Au NPs were tested by the well diffusion method for antifungal activity (zones of inhibition) against Microphyton gypseum (10±0.47 mm) and Trichophyton rubrum (13±1.03 mm). © 2012 Published by Elsevier B.V. All rights reserved.

Journal	Data powered by TypesetLetters in Applied Microbiology
Publisher	Data powered by TypesetWiley
ISSN	0266-8254
Open Access	Yes