scholarly journals Review of Biosynthesis Silver Nanoparticles by Microbiology

2020 ◽  
Vol 1 (01) ◽  
pp. 7-11
Author(s):  
Dr. Hawraa Natiq Kabroot Al-Fatlawy ◽  
Khwla Abd Al Kadhem Rahi ◽  
Diaa Sarhan Abd Al Zahra ◽  
Samara Rahem Hudud ◽  
Hussein Ali Hussein ◽  
...  

Nanotechnology is a multidisciplinary field that evolved within the past few decades and played a substantial role in the environment, industry, agriculture, and pharmacology. Nanoparticles are generally classified based on their dimensionality, morphology, composition, uniformity, and agglomeration. The shape, and morphology of nanoparticles play an essential role in their functionality and toxic effect on the environment and humans. In this review, we discuss the biosynthesis of nanoparticles from microbes. For the biological synthesis of nanoparticles, microbes have been exploited all over the globe. Microbes like bacteria, fungi, and yeasts are mostly preferred for nanoparticles (NPs) synthesis because of their fast growth rate, easy cultivation, and their ability to grow at ambient conditions of temperature, pH, and pressure. Applications of Nanoparticles is a field of research with tremendous prospects for the improvement of the diagnosis and treatment of human diseases. Microbial nanoparticles are found to have vigorous antibacterial activities. The nanoparticles' efficiency is probably due to their larger surface area for enhanced interaction with the micro-organisms. Nanoparticles adhere to the cell membrane and further penetrate inside by interacting with DNA, thereby interfering with the replication process or may attack the respiratory chain of pathogens. A similar bactericidal mechanism of silver nanoparticles obtained from endophytic bacterium Bacillus cereus was observed against pathogenic bacteria like Salmonella typhi, Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus, and Pseudomonas aeruginosa.

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1568
Author(s):  
Arinao Murei ◽  
Karen Pillay ◽  
Patrick Govender ◽  
Ntevheleni Thovhogi ◽  
Wilson M. Gitari ◽  
...  

In the present study, silver nanoparticles (AgNPs) were synthesized using both the chemical and biological methods and conjugated with Pyrenacantha grandiflora extracts. These were then characterized and evaluated for antimicrobial activities against multi-drug resistant pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella pneumonia, and Escherichia coli. Nanoparticles were analyzed with UV-visible spectrophotometer, transmission electron microscopy (TEM), and energy dispersive X-ray analysis (EDX). Silver nanoparticles, P. grandiflora extracts, and the conjugates were also analyzed with Fourier transform infrared spectroscopy (FTIR). As a result, quasi-sphere-shaped AgNPs with sizes ranging from 5 to 33 nm and spherically shaped AgNPs with sizes ranging from 3 to 25 nm were formed from chemical and biological synthesis, respectively. A well diffusion assay showed that the activity of silver nanoparticles was most improved with acetone extract against all tested bacteria with diameters in the range of 19–24 mm. The lowest MIC value of 0.0063 mg/mL against MRSA was observed when biologically synthesized AgNPs were conjugated with acetone and water extracts. Chemically synthesized silver nanoparticles showed the lowest MIC value of 0.0063 mg/mL against E. coli when conjugated with acetone and methanol extracts. This study indicates that silver nanoparticles conjugated with P. gandiflora tubers extracts exhibit strong antibacterial activities against multi-drug resistant bacterial pathogens. Therefore, biosynthesized conjugates could be utilized as antimicrobial agents for effective disease management due to the synergistic antibacterial activity that was observed.


Scientifica ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Baker Syed ◽  
Hoovinakola Chinnappa Yashavantha Rao ◽  
Mysore Nagalingaswamy Nagendra-Prasad ◽  
Ashwini Prasad ◽  
Ballagere Puttaraju Harini ◽  
...  

The present investigation aims to evaluate biomimetic synthesis of silver nanoparticles using endophytic bacterium EH 419 inhabitingEuphorbia hirtaL. The synthesized nanoparticles were initially confirmed with change in color from the reaction mixture to brown indicating the synthesis of nanoparticles. Further confirmation was achieved with the characteristic absorption peak at 440 nm using UV-Visible spectroscopy. The synthesized silver nanoparticles were subjected to biophysical characterization using hyphenated techniques. The possible role of biomolecules in mediating the synthesis was depicted with FTIR analysis. Further crystalline nature of synthesized nanoparticles was confirmed using X-ray diffraction (XRD) with prominent diffraction peaks at 2θwhich can be indexed to the (111), (200), (220), and (311) reflections of face centered cubic structure (fcc) of metallic silver. Transmission electron microscopy (TEM) revealed morphological characteristics of synthesized silver nanoparticles to be polydisperse in nature with size ranging from 10 to 60 nm and different morphological characteristics such as spherical, oval, hexagonal, and cubic shapes. Further silver nanoparticles exhibited bactericidal activity against panel of significant pathogenic bacteria among whichPseudomonas aeruginosawas most sensitive compared to other pathogens. To the best of our knowledge, present study forms first report of bacterial endophyte inhabitingEuphorbia hirtaL. in mediating synthesizing silver nanoparticles.


Author(s):  
ANNAMALAI MADURAM ◽  
RAJU KAMARAJ

Objectives: The objectives of the study were to study the antibacterial activity for the various extracts of Clausena dentata against human pathogens. Clausena (Rutaceae) is a genus of about 23 species of unarmed trees and shrubs. The stem bark of C. dentata is used in veterinary medicine for the treatment of wounds and sprains. Even though C. dentata has a lot of potential medical uses, the study of microbiological properties is very scarce. Methods: The plant C. dentata was collected from Kadagaman, near Tiruvannamalai, Tamil Nadu, India, and authenticated by Centre for Advanced Study in Botany, University of Madras, Chennai. The dry powder of stem bark was extracted with hexane, chloroform, and methanol. The extracts were subjected to qualitative phytochemical screening and antibacterial activity against human pathogenic bacteria such as Escherichia coli, Salmonella Typhi, Klebsiella pneumonia, Vibrio cholerae, and Staphylococcus aureus and compared with ciprofloxacin. Results: Qualitative chemical tests revealed the presence of various phytochemicals such as alkaloids, glycosides, carbohydrate, proteins and amino acids, phytosterols, and volatile oil. The antibacterial activity result reveals that all the extracts were are more active against V. cholerae. The activity against Pseudomonas aeruginosa was mild. Conclusion: The activity against V. cholerae was comparable with that of 5 μg/mL ciprofloxacin at the concentration of C. dentata 40 μg/mL. The orders of antibacterial activity against human pathogenic bacteria are hexane, methanol, and chloroform extract of C. dentata.


Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 299
Author(s):  
Reetika Singh ◽  
Christophe Hano ◽  
Gopal Nath ◽  
Bechan Sharma

Carissa carandas L. is traditionally used as antibacterial medicine and accumulates many antioxidant phytochemicals. Here, we expand this traditional usage with the green biosynthesis of silver nanoparticles (AgNPs) achieved using a Carissa carandas L. leaf extract as a reducing and capping agent. The green synthesis of AgNPs reaction was carried out using 1mM silver nitrate and leaf extract. The effect of temperature on the synthesis of AgNPs was examined using room temperature (25 °C) and 60 °C. The silver nanoparticles were formed in one hour by stirring at room temperature. In this case, a yellowish brown colour was developed. The successful formation of silver nanoparticles was confirmed by UV–Vis, Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) analysis. The characteristic peaks of the UV-vis spectrum and XRD confirmed the synthesis of AgNPs. The biosynthesised AgNPs showed potential antioxidant activity through DPPH assay. These AgNPs also exhibited potential antibacterial activity against human pathogenic bacteria. The results were compared with the antioxidant and antibacterial activities of the plant extract, and clearly suggest that the green biosynthesized AgNPs can constitute an effective antioxidant and antibacterial agent.


Author(s):  
Mohammed M Matin ◽  
Mohammad Ibrahim ◽  
Md Shafiqur Rahman

A number of 2,3-di-O-acyl derivatives (6-11) of methyl 4-O-acetyl-a-Lrhamnopyranoside (5) obtained by using various acylating agents were screened for in vitro antifungal activity against four plant pathogenic fungi, viz., Alternaria alternata, Curvularia lunata. Fusarium equiseti and Macrophomina phaseolina. These compounds were also screened for in vitro antibacterial activity against ten human pathogenic bacteria, viz., Bacillus subtilis, Bacillus cereus, Bacillus megaterium, Staphylococcus aureus, Escherichia coli, INABA ET (Vibrio), Pseudomonas species, Salmonella paratyphi, Shigella dysenteriae and Salmonella typhi. The study reveal that these 4-O-acetyl-?-L-rhamnopyranoside derivatives are more prone towards antifungal activities than that of antibacterial activities. DOI: http://dx.doi.org/10.3329/cujbs.v3i1.13404 The Chittagong Univ. J. B. Sci.,Vol. 3(1&2):33-43, 2008


2020 ◽  
Author(s):  
Hannah Cynthia Samuel ◽  
Saraswathy Nachimuthu ◽  
Balaji Sadhasivam ◽  
Ramalingam Ponnusamy

2019 ◽  
Author(s):  
M.K. Rajesh ◽  
K.S. Muralikrishna ◽  
Swapna S. Nair ◽  
B. Krishna Kumar ◽  
T.M. Subrahmanya ◽  
...  

ABSTRACTGreen synthesis of nanoparticles (NPs) involves the use of diverse extracts of biological origin as substrates to synthesize nanoparticles and can overcome the hazards associated with chemical methods. Coconut inflorescence sap, which is unfermented phloem sap obtained by tapping of coconut inflorescence, is a rich source of sugars and secondary metabolites. In this study, coconut inflorescence sap was used to synthesize silver nanoparticles (AgNPs). We have initially undertaken metabolomic profiling of coconut inflorescence sap from West Coast Tall cultivar to delineate its individual components. Secondary metabolites constituted the major portion of the inflorescence sap along with sugars, lipids and, peptides. The concentration of silver nitrate, inflorescence sap and incubation temperature for synthesis of AgNPs were optimized. Incubating the reaction mixture at 40°C was found to enhance AgNP synthesis. The AgNPs synthesized were characterized using UV-Visible spectrophotometry, X-Ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). Antimicrobial property of AgNP was tested in tissue culture of arecanut (Areca catechu L.) where bacterial contamination (Bacillus pumilus) was a frequent occurrence. Significant reduction in the contamination was observed when plantlets were treated with aqueous solutions of 0.01, 0.02 and 0.03% of AgNPs for one hour. Notably, treatment with AgNPs did not affect growth and development of the arecanut plantlets. Cytotoxicity of AgNPs was quantified in HeLa cells. Viability (%) of HeLa cells declined significantly at 10 ppm concentration of AgNP and complete mortality was observed at 60 ppm. Antimicrobial properties of AgNPs synthesized from inflorescence sap were also evaluated and confirmed in human pathogenic bacteria viz., Salmonella sp., Vibrio parahaemolyticus, and Escherichia coli. The study concludes that unfermented inflorescence sap, with above neutral pH, serves as an excellent reducing agent to synthesize AgNPs from Ag+. Graphical abstract


2021 ◽  
Vol 5 (1) ◽  
pp. 436-444
Author(s):  
Sabiu Shitu ◽  
M. Attahiru ◽  
F. A. Iliya

The antibacterial activity of Tokar sha; a local traditional medication widely used by many people in North-west zone of Nigeria especially Sokoto, Kebbi and Zamfara against enteric infections were examined against some clinical isolates of pathogenic bacteria (Staphylococcus aureus, Escherichia coli, Bacillus cereus and Salmonella typhi) using agar well diffusion method. The pattern of inhibition varied with the tokar sha concentrations and the organisms tested. The tokar sha was more effective on E. coli with a maximum zone of growth inhibition of 25mm at 35mg/ml followed by B. cereus (20mm). However, S. aureus and S. typhi were resistant to tokar sha at all concentrations tested. The minimum inhibitory concentrations (MIC) were found to be 35mg/ml for both E. coli and B. cereus. The antibacterial activities exhibited by tokar sha in this study could be attributed to the presence of its constituents which signifies the potential of the tokar sha as a therapeutic agent. These findings may justify the ethnomedicinal use of tokar sha as an antibacterial agent against enterobacteria


2020 ◽  
Vol 5 (2) ◽  

Nanotechnology has evolved a great deal. Biological synthesis of nanoparticles and silver nanoparticles in particular has been widely studied. The current review focuses on different studies across the globe that adopted different methods and biological system to synthesize silver nanoparticles. Special emphasis has been given to North East India as many of the studies from this part of the world tried to synthesize functional nanoparticles based on indigenous medicinal plant extract.


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