Green synthesis of silver nanoparticles using Bacillus cereus, an endophytic bacterium isolated from Garcinia xanthochymus

Author(s):  
Swetha Sunkar ◽  
C. Valli Nachiyar
Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3220 ◽  
Author(s):  
Tahmina Monowar ◽  
Md. Rahman ◽  
Subhash Bhore ◽  
Gunasunderi Raju ◽  
Kathiresan Sathasivam

Antibiotic resistance is one of the most important global problems currently confronting the world. Different biomedical applications of silver nanoparticles (AgNPs) have indicated them to be promising antimicrobial agents. In the present study, extracellular extract of an endophytic bacterium, Pantoea ananatis, was used for synthesis of AgNPs. The synthesized AgNPs were characterized by UV–Vis spectroscopy, FTIR, transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), and Zeta potential. The antimicrobial potential of the AgNPs against pathogenic Staphylococcus aureus subsp. aureus (ATCC 11632), Bacillus cereus (ATCC 10876), Escherichia coli (ATCC 10536), Pseudomonas aeruginosa (ATCC 10145) and Candida albicans (ATCC 10231), and multidrug resistant (MDR) Streptococcus pneumoniae (ATCC 700677), Enterococcus faecium (ATCC 700221) Staphylococcus aureus (ATCC 33592) Escherichia coli (NCTC 13351) was investigated. The synthesized spherical-shaped AgNPs with a size range of 8.06 nm to 91.32 nm exhibited significant antimicrobial activity at 6 μg/disc concentration against Bacillus cereus (ATCC 10876) and Candida albicans (ATCC 10231) which were found to be resistant to conventional antibiotics. The synthesized AgNPs showed promising antibacterial efficiency at 10 µg/disc concentration against the MDR strains. The present study suggests that AgNPs synthesized by using the endophytic bacterium P. ananatis are promising antimicrobial agent.


2020 ◽  
Vol 21 (3) ◽  
pp. 206-218 ◽  
Author(s):  
Sadia Nazer ◽  
Saiqa Andleeb ◽  
Shaukat Ali ◽  
Nazia Gulzar ◽  
Tariq Iqbal ◽  
...  

Background: Multi-drug resistance in bacterial pathogens is a major concern of today. Green synthesis technology is being used to cure infectious diseases. Objectives: The aim of the current research was to analyze the antibacterial, antioxidant, and phytochemical screening of green synthesized silver nanoparticles using Ajuga bracteosa. Methods: Extract of A. bracteosa was prepared by maceration technique. Silver nanoparticles were synthesized using A. bracteosa extract and were confirmed by UV-Vis spectrophotometer, Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The antibacterial, anti-biofilm, cell proliferation inhibition, TLC-Bioautography, TLC-Spot screening, antioxidant, and phytochemical screening were also investigated. Results: UV-Vis spectrum and Scanning electron microscopy confirmed the synthesis of green nanoparticles at 400 nm with tube-like structures. FTIR spectrum showed that functional groups of nanoparticles have a role in capping and stability of AgNP. Agar well diffusion assay represented the maximum antibacterial effect of ABAgNPs against Escherichia coli, Klebsiella pneumoniae, Streptococcus pyogenes, Staphylococcus aureus, and Pseudomonas aeruginosa at 0.10 g/mL concentration compared to ABaqu. Two types of interactions among nanoparticles, aqueous extract, and antibiotics (Synergistic and additive) were recorded against tested pathogens. Crystal violet, MTT, TLC-bio-autography, and spot screening supported the findings of the antibacterial assay. Highest antioxidant potential effect in ABaqu was 14.62% (DPPH) and 13.64% (ABTS) while 4.85% (DPPH) and 4.86% (ABTS) was recorded in ABAgNPs. Presence of phytochemical constituents showed pharmacological importance. Conclusion: It was concluded that green synthesis is an innovative technology in which natural products are conjugated with metallic particles and are used against infectious pathogens. The current research showed the significant use of green nanoparticles against etiological agents.


2017 ◽  
Vol 7 (1) ◽  
pp. 104-112 ◽  
Author(s):  
Alireza Ebrahiminezhad ◽  
Saeed Taghizadeh ◽  
Aydin Berenjian ◽  
Fatemeh Heidaryan Naeini ◽  
Younes Ghasemi

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1007
Author(s):  
Azam Ali ◽  
Mariyam Sattar ◽  
Fiaz Hussain ◽  
Muhammad Humble Khalid Tareen ◽  
Jiri Militky ◽  
...  

The versatile one-pot green synthesis of a highly concentrated and stable colloidal dispersion of silver nanoparticles (Ag NPs) was carried out using the self-assembled tannic acid without using any other hazardous chemicals. Tannic acid (Plant-based polyphenol) was used as a reducing and stabilizing agent for silver nitrate in a mild alkaline condition. The synthesized Ag NPs were characterized for their concentration, capping, size distribution, and shape. The experimental results confirmed the successful synthesis of nearly spherical and highly concentrated (2281 ppm) Ag NPs, capped with poly-tannic acid (Ag NPs-PTA). The average particle size of Ag NPs-PTA was found to be 9.90 ± 1.60 nm. The colloidal dispersion of synthesized nanoparticles was observed to be stable for more than 15 months in the ambient environment (25 °C, 65% relative humidity). The synthesized AgNPs-PTA showed an effective antimicrobial activity against Staphylococcus Aureus (ZOI 3.0 mM) and Escherichia coli (ZOI 3.5 mM). Ag NPs-PTA also exhibited enhanced catalytic properties. It reduces 4-nitrophenol into 4-aminophenol in the presence of NaBH4 with a normalized rate constant (Knor = K/m) of 615.04 mL·s−1·mg−1. For comparison, bare Ag NPs show catalytic activity with a normalized rate constant of 139.78 mL·s−1·mg−1. Furthermore, AgNPs-PTA were stable for more than 15 months under ambient conditions. The ultra-high catalytic and good antimicrobial properties can be attributed to the fine size and good aqueous stability of Ag NPs-PTA. The unique core-shell structure and ease of synthesis render the synthesized nanoparticles superior to others, with potential for large-scale applications, especially in the field of catalysis and medical.


AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Susanna Gevorgyan ◽  
Robin Schubert ◽  
Mkrtich Yeranosyan ◽  
Lilit Gabrielyan ◽  
Armen Trchounian ◽  
...  

AbstractThe application of green synthesis in nanotechnology is growing day by day. It’s a safe and eco-friendly alternative to conventional methods. The current research aimed to study raw royal jelly’s potential in the green synthesis of silver nanoparticles and their antibacterial activity. Royal jelly served as a reducing and oxidizing agent in the green synthesis technology of colloidal silver nanoparticles. The UV–Vis maximum absorption at ~ 430 nm and fluorescence emission peaks at ~ 487 nm confirmed the presence of Ag NPs. Morphology and structural properties of Ag NPs and the effect of ultrasound studies revealed: (i) the formation of polydispersed and spherical particles with different sizes; (ii) size reduction and homogeneity increase by ultrasound treatment. Antibacterial activity of different concentrations of green synthesized Ag NPs has been assessed on Gram-negative S. typhimurium and Gram-positive S. aureus, revealing higher sensitivity on Gram-negative bacteria.


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