DOI: https://doi.org/10.4316/fens.2022.014 

  143 

 

Journal homepage: http://fens.usv.ro/index.php/FENS 
Journal of Faculty of Food Engineering,  

Ştefan cel Mare University of Suceava, Romania  

Volume XXI, Issue 2 - 2022, pag. 143 -  151 

 

 

MICROBIAL SYNTHESIS OF SILVER NANOPARTICLES BY ENTEROCOCCUS 

FAECALIS STRAIN MI103 

 Jane NSOFOR1, Imade Yolanda NSA1, Busayo Tosin AKINYEMI1,   

Adewale Kayode OGUNYEMI1, *Matthew Olusoji ILORI1 
1Department of Microbiology, University of Lagos, Nigeria  

milori@unilag.edu.ng,  

*Corresponding author:  

Received 1st January 2022, accepted 25th June 2022 

 
Abstract: Silver nanoparticles (AgNPs) have recently attracted attention for their potential as a source 

of new antimicrobials, with the potential to better fight a wide range of pathogenic bacteria. 

Nanomaterials are now commonly used for the production of industrial and domestic items.  As a result 

of increase in the menace and threats to live by antibiotic-resistant bacteria, nanoparticles have been 

proposed as alternative for its control. Enterococcus faecalis, strain MI103, was selected out of four 

isolates obtained from a soil sample and identified using 16S rRNA gene sequencing method. The 

selected bacterial isolate synthesized AgNPs by reduction of Silver nitrate (AgNO3) solution (incubated 

for 2 days at room temperature). Colour development from pale yellow to brown was observed which 

indicated the extracellular production of AgNPs.  AgNPs was further characterized by UV/VIS 

spectroscopy, Scanning Electron Microscopy (JOEL-JSM-7660F) (shape) and Energy Dispersive X-ray 

(EDX) (composition).  The synthesized AgNPs ranged in size of 90-100 nm and were of cylindrical 

shape. It was found that the highest quantity of AgNO3 was produced at pH 7. The synthesized AgNPs 

had strong bactericidal activity against MRSA.  

Keywords: Silver nanoparticles (AgNPs), Antimicrobials, Enterococcus faecalis, Nanotechnology, 

Nanoparticles, 16SrRNA  

  

1. Introduction 

 

                                                                                                                                                                                                                                                                                                                                                                 

The development of antibiotic resistance 

has posed a significant threat, first to health 

and wellness and then to food security 

globally.  As a result of increasing abuse of 

antibiotics in health and industrial use, 

antibiotic resistance has significantly 

increased [1, 2]. The development of 

antimicrobial drug resistance is making it 

increasingly difficult to treat otherwise 

routine infections effectively and this has 

created a pressing need for new 

antimicrobials. The costs associated with 

antibiotic resistance are higher, hospital 

stays are longer, and mortality increases [3]. 

Health care costs are rising due to 

antibiotic-resistant infections [4]. 

Antibiotics used without a prescription 

results in the emergence and spread of 

resistance. Actions must therefore be taken 

immediately to prevent infections and 

minor injuries from killing people around 

the world [5].  

AgNPs have been proposed as an 

alternative to antibiotics in the race to curb 

the huge burden of infections that cannot be 

handled with the currently known 

antimicrobials. Nanoparticles are molecules 

with a minimum dimension of 100 

nanometers [6]. In addition to chemical and 

biological sensing [7], CO2 capturing [8, 9] 

and drug delivery [10], nanoparticles have 

found numerous applications. A number of 



Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava 

Volume XXI, Issue 2 – 2022 

 

 

Jane NSOFOR, Imade Yolanda NSA, Busayo Tosin AKINYEMI, Adewale Kayode OGUNYEMI, Matthew Olusoji ILORI, Microbial 

Generation of Silver Nanoparticles by Synthesizing Enterococcus feacalis strain MI103, Food and Environment Safety, 

Volume XXI, Issue 2 – 2022, pag. 143 –  151
 

144 

studies have shown that silver nanoparticles 

disrupt cell-walls and cellular respiration, as 

well as bind to them [11, 12, 13]. Several 

studies have shown that nanosilver is 

bactericidal against Gram-negative and 

Gram-positive bacteria. However, the 

underlying bactericidal mechanism is still 

unknown [14, 15, 16]. In a study by 

Morones et al. [15], four Gram negative 

bacteria, E. coli, V. cholerae, P. aeruginosa 

and S. typhus, were found to exhibit 

antibacterial activities using silver 

nanoparticles and had been shown to attach 

to the surface of the cell membrane, adhere 

bacteria, and discharge silver ions. There 

have been other studies with Gram positive 

bacteria, such as Staphylococcus aureus 

[15]. By examining the antibacterial 

properties of synthesized silver 

nanoparticles against drug-resistant 

bacteria, this study aims to determine the 

effectiveness of the biotechnolgicaly 

generated nanoparticles. Towards this end, 

methicillin-resistant     Staphylococcus 

aureus (MRSA) was used.  

 

2. Matherials and methods 

 

2.1 Collection of Samples 
Soil and water samples including loamy 

soil, oil contaminated sandy soil, seawater 

and tap water were collected in sterilized 

bottles from Lagos Mainland Local 

Government Area (LGA) of Lagos State 

and transported immediately to 

microbiological Laboratory for analysis. 

 

2.2 Isolation of bacteria and biosynthesis 

of silver nanoparticles. 

Bacteria was isolated by 10-fold serial 

dilution. About 0.2 ml aliquot were plated 

on Luria Bertani (LB) plate agar. Isolates 

were purified on LB agar medium in order 

to obtain pure cultures. The pure cultures 

were stored at 4°C on agar slant for further 

studies. The pure isolate was mass produced 

by cultivation on LB broth at 37°C for 24h 

on rotary shaker (150rpm). After 

incubation, cultures supernatants were 

obtained after centrifugation at 10,000 rpm 

for 10 min. One hundred millilitres of cell 

free supernatant were added to 50 ml of 

prepared 10 mM solution of AgNO3 

(1.7g/L). Three replicates were used for 

each strain. While cell free supernatant 

without AgNO3 served as control [17]. The 

flasks were left for 24 h at room temperature 

in the dark to prevent photo catalytic action.  

 

2.3 Characterization of Silver 

nanoparticles  

Extracellular synthesized silver 

nanoparticles (AgNPs) produced by cell 

free cells supernatant of strains of isolated 

bacterial strains, obtained after centrifuging 

at 10,000 rpm for 10 minutes, were rinsed 

several times and dried. They were then 

characterized by UV/VIS spectroscopy in 

range of 200-700 nm [18]. The shape of the 

nanoparticles was determined by Scanning 

Electron Microscopy (JOEL-JSM-7660F) 

and the composition of the nanoparticles 

was determined by Energy Dispersive X-

ray (EDX) [19].  

 

2.4 Characterization of antibacterial 

activity of nanoparticles 

Disc papers were soaked with 20 μL of 30 

mg/L AgNPs suspensions and placed on the 

culture dish, incubated at 37°C for 24 h. For 

the control study, deionized water and 

generated Ag suspension soaked disc was 

also placed on the dish. These were then 

placed on Mueller Hilton agar that 

contained MRSA with approximate density 

of initial inoculum of about 0.5 Mc Farland 

turbidity standard. Sterilized cut filter 

papers that had been soaked in the cell-free 

water extract alone and AgNO3 were used 

as control. Plates were incubated overnight 

at 35°C for 18 h and observed for the 

presence of zones of inhibition.  

 

2.5 Identification of synthesizing bacteria 



Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava 

Volume XXI, Issue 2 – 2022 

 

 

Jane NSOFOR, Imade Yolanda NSA, Busayo Tosin AKINYEMI, Adewale Kayode OGUNYEMI, Matthew Olusoji ILORI, Microbial 

Generation of Silver Nanoparticles by Synthesizing Enterococcus feacalis strain MI103, Food and Environment Safety, 

Volume XXI, Issue 2 – 2022, pag. 143 –  151
 

145 

The bacteria isolate that produced the 

largest quantity of silver nanoparticles was 

identified using 16SrRNA gene sequencing 

method. Genomic DNA (gDNA) was 

extracted from the bacterial isolates using 

Zymo Research Bacterial DNA Minipreptm 

Kit (Zymo Research Corp USA). The DNA 

concentrations was determined using a 

NanoDrop 2000c spectrophotometer 

(ThermoFisher). Polymerase chain reaction 

(PCR) was used to amplify the 16S rRNA 

gene of the isolate using the primer pair 27F 

(5′-AGAGTTTGATCCTGGCTCAG-3) 

and 1492R 5’-GGTTACCTTGT 

TACGACTT-3) [20] was done in an Pielter 

thermal cycler (MJ Research Series) under 

the following conditions: initial 

denaturation step was 95°C for 5 minutes 

followed by 30 amplification cycles of 30 

seconds at 95°C; 1 minute at 50°C and 1 

minute 30 seconds at 72°C; and then a final 

extension step of 10 minutes at 72°C. The 

amplification product was separated on a 

1.5% agarose gel and electrophoresis was 

carried out at 80 V for 1 hour 30 minutes. 

After electrophoresis, DNA bands were 

visualized by ethidium bromide staining. 

DNA sequences were processed by Basic 

Local Alignment Search Tool (BLAST) 

program 

(http://www.ncbi.nlm.nih.gov/BLAST). 

 

2.6 Effect of pH on nanoparticle 

production and efficacy 
The synthesizing AgNPs bacterial isolate 

was grown in LB broth at different pH 2, 7 

and 9. The resulting suspensions were 

centrifuged and 100 ml of supernatant from 

each flask was inoculated with 50ml of 

10mM of AgNO3 and incubated in 

darkness. Production of nanoparticle was 

observed for in both flasks. 

 

2.7 Test of AgNPs against Methicillin-

resistant Staphylococcus aureus (MRSA)  

Nanoparticles produced were tested against 

MRSA. Sterile filter papers were cut, 

soaked in the different nanoparticles 

produced and placed on plates already 

swabbed with an inoculum of MRSA and 

left to incubate overnight. Zones of 

inhibition were measured. 

 

2.8 Evaluation of antibacterial activity, 

minimum inhibitory concentration 

(MIC) and minimum bactericidal 

concentration (MBC) of silver 

nanoparticles (AgNPs).  

Kirby–Bauer Disk Diffusion Susceptibility 

Test method described by Bauer et al. [20] 

was employed for antibacterial activity of 

AgNPs against the MRSA pathogen. Sterile 

cotton swab was used for spreading the 

bacterial strain on Mueller-Hinton agar 

(MHA) (Merck, Germany). Sterile blank 

antimicrobial susceptibility disk was used 

in the test. The AgNPs concentration of 

10mg/ml, 5mg/ml, 2mg/ml and 1mg/ml was 

loaded into the disks and was used for the 

test. The bacteria strain was spread on the 

Mueller-Hinton agar (MHA) (Merck, 

Germany) using sterile cotton swab. Sterile 

blank antimicrobial susceptibility disk was 

used in the test.  

The antimicrobial efficacy determination by 

using method described by CLSI M07-A8. 

Here, observation for visible growth in the 

LB broth. The synthesized nanoparticles 

(4g) were suspended in 200 ml of LB broth 

using an ultrasonic homogenizer. The 

resulting (20 mg/ml) concentration was 

used as the stock concentrations. MIC was 

carried by inoculating 1ml of peptone water 

containing MRSA of approximate density 

of a 0.5 McFarland turbidity standard in all 

tubes. The tubes were incubated at 35°C for 

24 hours and monitored for growth. The 

lowest concentration of silver nanoparticles 

where no visible growth is seen in the tubes 

is the MIC endpoint. However, the turbidity 

before and after the incubation was noted. 

MBC was carried out by inoculating 0.1ml 

from tubes that showed no visible growth 

(no turbidity) onto LB agar and incubating 

http://www.ncbi.nlm.nih.gov/BLAST
https://www.frontiersin.org/articles/10.3389/fmicb.2018.01555/full#B3


Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava 

Volume XXI, Issue 2 – 2022 

 

 

Jane NSOFOR, Imade Yolanda NSA, Busayo Tosin AKINYEMI, Adewale Kayode OGUNYEMI, Matthew Olusoji ILORI, Microbial 

Generation of Silver Nanoparticles by Synthesizing Enterococcus feacalis strain MI103, Food and Environment Safety, 

Volume XXI, Issue 2 – 2022, pag. 143 –  151
 

146 

for 24 hours at 35°C. MBC endpoint is the 

lowest concentration that is able to kill 

99.9% of bacterial population. This was 

obtained by noting the pre- and post- 

incubated agar plates for the presence or 

absence of bacteria.  

 

3. Results  
 

3.1 Biosynthesis of silver nanoparticles 

Among the four bacterial isolates, MI103 

produced the highest quantity of brown 

precipitate (5g) indicating the presence of 

silver nanoparticles. One (one quarter) 

produced white precipitate and the other 

quarter of the (isolates) produced no 

precipitate. As a result of being the highest 

producer, MI103 was selected for further 

testing (Table 1). A colour change from pale 

yellow to brown was observed which was 

an indication of the extracellular synthesis 

of AgNPs. The precipitate was obtained by 

centrifugation at 10,000 rpm for 10 min and 

oven dried. 
Table 1:  

Screening for Production of Silver Nanoparticles 

 

3.2 Characterisation of silver 

nanoparticles 

Synthesized silver nanoparticles were 

characterized using UV-VIS 

spectrophotometry, scanning electron 

microscopy and Energy Dispersive X-ray 

(EDX). Figure 1 showed concentration of 

synthesized silver nanoparticles generated 

by isolate MI103 at different wavelengths. 

The absorbance obtained was within the 

range of 1.1 to 1.986 for synthesized silver 

nanoparticles. There was a steady rise in the 

absorbance readings between wave length 

of 200 nm to 300 nm, followed by a spike 

in absorbance readings at wavelengths 

between 380 nm and 426 nm until a decline 

occurred at 441 nm (Figure 1). Scanning 

electron micrograph (SEM) of synthesized 

silver nanoparticles showed that the 

particles were cylindrical in shape, highly 

clustered, dense and colloidal in nature 

(Figure 2). The nanoparticles are about 90-

100 nm (verify size by measuring a particle 

calculating with 15nm scale bar) in size. 

Energy Dispersive X-ray (EDX) of silver 

nanoparticles showed that the particles 

contained several elements in the following 

concentrations: Silver (51.85%), Gold 

(2.70%), Oxygen (20.40%), Magnesium 

(2.44%), Sodium (5.90%), Silicon (3.75%), 

Calcium (2.26%) and Carbon (7.09%) 

(Figure 3). 

 
 

Fig. 1. Concentration of synthesized silver 

nanoparticles generated from MI103 at different 

wavelengths 

 

3.3 Antibacterial efficacy, minimum 

inhibitory concentration (MIC) and 

minimum bactericidal concentration 

(MBC) of silver nanoparticles (AgNPs)  
The antibacterial activity of AgNPs was 

determined against MRSA. The results for 

disk diffusion test, MIC and MBC of the 

AgNPs are summarized in Tables 2 and 3.

 

200 400 600 800
0.0

0.5

1.0

1.5

2.0

2.5

Wavelength (nm)

A
b

so
rb

an
ce

 (
O

.D
)

Organism 

code 

Precipitate 

produced 

Quantity 

MI101 Brownish 

precipitate 

0.8g 

MI102 Whitish precipitate 0.5g 

MI103 Brownish 

precipitate 

5g 

MI104 No precipitate - 



Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava 

Volume XXI, Issue 2 – 2022 

 

 

Jane NSOFOR, Imade Yolanda NSA, Busayo Tosin AKINYEMI, Adewale Kayode OGUNYEMI, Matthew Olusoji ILORI, Microbial 

Generation of Silver Nanoparticles by Synthesizing Enterococcus feacalis strain MI103, Food and Environment Safety, 

Volume XXI, Issue 2 – 2022, pag. 143 –  151
 

147 

 
 

Fig. 2. Electron micrograph of silver nanoparticles generated from isolate MI103 

 

 
Fig. 3. Energy dispersive x-ray (EDX) of MI103 generated silver nanoparticles

For the disk diffusion test, the presence of 

clear zone around the AgNPs disk 

suggesting that the AgNPs possessed 

antibacterial activity which is able to inhibit 

the growth of the MRSA. The visible clear 

zone produced by AgNPs against MRSA 

bacteria is showed in Supplementary Plate 

1. MRSA showed zones of inhibition 

ranging from 18 mm to  

21 mm in diameter (Table 2). Thus, the 

antibacterial activity of Ag nanoparticles 

was bactericidal.  

As showed in Table 3, MRSA showed MIC 

and MBC value of 5g/ml, respectively. In 

the study, the MIC and MBC value showed 

that MRSA was susceptible to AgNPs. 
 

Table 2.  

Antimicrobial (Antibacterial) Sensitivity Test (AST) of AgNPs against MRSA 

 

Ag Nanoparticle 

Discs 

1 2 3 4 5 6 7 8 9 10 

Zone of inhibition 

against MRSA (nm) 

18 21 21 18 20 19 20 18 20 18 

                       

 

 

 

 

 

https://www.frontiersin.org/articles/10.3389/fmicb.2018.01555/full#F1


Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava 

Volume XXI, Issue 2 – 2022 

 

 

Jane NSOFOR, Imade Yolanda NSA, Busayo Tosin AKINYEMI, Adewale Kayode OGUNYEMI, Matthew Olusoji ILORI, Microbial 

Generation of Silver Nanoparticles by Synthesizing Enterococcus feacalis strain MI103, Food and Environment Safety, 

Volume XXI, Issue 2 – 2022, pag. 143 –  151
 

148 

 

Table 3.  

Determination of MIC and MBC of AgNPs 

 

MIC (mg/ml) Observation MBC (mg/ml) Observation/any other description 

20 Clear 20 No growth 

10 Clear 10 No growth 

5 Clear 5 No growth 

2 Turbid 2 No growth 

1 Turbid 1 No growth 

 

 

Table 4.  

Effect of pH on Production and Antimicrobial activity of AgNPs generated by MI103 

 

 

pH 

Effect on production Effect on antimicrobial 

activity 

Growth in LB broth (after 24 hours) Quantity of nanoparticles 

produced 

Average zone of inhibition 

(mm) 

2 Clear - - 

7 Turbid 4.8g 25 

9 Slightly Turbid 0.7g 10 

 

3.4 Silver nanoparticle synthesizing   

bacteria 

Isolate MI103, the highest producer of Ag 

nanoparticles, was identified as 

Enterococcus faecalis strain MI103 based 

on 16S rRNA gene sequencing method. The 

sequence (1506bp) was compared to 

sequences in GenBank by BLAST. 

 

3.5 pH and nanoparticle 

production/activity 
The optimal pH was obtained at 2 with no 

turbidity and precipitate observed in the LB 

after incubation in darkness. While at pH 7, 

the suspension was turbid and a brown 

precipitate formed. Whereas at pH 9, less 

turbidity and small mass (0.7 g) of 

precipitate formed (Table 3). MRSA were 

more sensitive to Ag nanoparticles at pH 7 

than at pH of 9 by a ~ 2.5-fold difference in 

their zones of inhibition, 25 mm and 10 mm 

respectively (Table 3). The minimum 

inhibitory concentration of the synthesized 

nanoparticles was about 5 mg/ml (Table 4) 

as turbidity was observed at concentrations 

below the MIC indicating growth of 

MRSA. In addition, MBC of the 

synthesized nanoparticles is 5 mg/ml (Table 

4) as no growth was observed after plating 

on LB agar from concentrations of 5 mg/ml 

and above which initially showed no 

turbidity. 

 

4. Discussion 

Research into alternative methods to cure 

infections has increased following reports 

of infections caused by antibiotic-resistant 

organisms. In this regard, nanoparticles 

have been used [21]. Because of their large 

surface area to volume ratio, silver 

nanoparticles have the most remarkable 

antimicrobial properties of all 

nanoparticles. Moreover, researchers are 



Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava 

Volume XXI, Issue 2 – 2022 

 

 

Jane NSOFOR, Imade Yolanda NSA, Busayo Tosin AKINYEMI, Adewale Kayode OGUNYEMI, Matthew Olusoji ILORI, Microbial 

Generation of Silver Nanoparticles by Synthesizing Enterococcus feacalis strain MI103, Food and Environment Safety, 

Volume XXI, Issue 2 – 2022, pag. 143 –  151
 

149 

interested in the growth of microbial 

resistance against metal ions, antibiotics, 

and the development of resistant strains [22, 

23]. It is clear that these particles possess 

good antimicrobial properties; however, 

their exact mechanism of action remains 

unknown [24] plus the toxicological 

challenges that may result in vivo. There is 

evidence that AgNPs have action against a 

wide array of microbes due to the multiple 

mechanisms they utilize, including their 

ability to destroy drug-resistant bacteria, 

fungi, and viruses [25, 26, 27, 28, 29, 30]. It 

is true that there are various methods for 

synthesizing nanoparticles, but biological 

synthesis, which relies on plants or 

microbes, is environmentally and 

economically friendly [31]. A screen for 

microorganisms producing AgNP revealed 

Enterococcus faecalis to be the best 

candidate identified via the 16S rRNA gene 

sequence. Further characterization of 

biosynthesized AgNPs was achieved using 

UV-Vis spectroscopy and the peak was 

located between 420-440 nm [32]. There 

has been well documented evidence that 

this peak is caused by an interaction 

between two metal nanoparticles of 

different sizes ranging from 2 to 100 

nanometers [33]. This study supports the 

findings of Jeevan et al. [17], where the 

peak was found between 420-430nm and 

[32], where the peak was at 420nm.  It was 

reported [33] that extracts of Parkia 

speciosa Hassk pods were used in lieu of 

microbes, and the peak was found at 445 

nm.  SEM studies showed that the 

nanoparticles were cylindrical, dense, and 

clustered. Possibly, this is due to clumping 

and drying the samples prior to analysis. 

Similarly, Is [33] reports clumping. 

Compared to AgNPs with sizes ranging 

from 10 to 49 nanometers, these 

nanoparticles are 90-100 nm in size and 

irregular shape of synthesized by 

Pseudomonas aeruginosa (15-30nm) [34] 

and Escherichia coli (20-30nm) [35].  This 

study used Energy Dispersive X-ray (EDX) 

to examine AgNps which contained several 

elements, with silver being the most 

abundant. Several elements are present in 

AgNps, but silver is the most abundant, and 

the study examined it using Energy 

Dispersive X-ray (EDX). Is [33] came up 

with the same findings. It was found that 

AgNPs were extremely effective against 

methicillin - resistant Staphylococcus 

aureus. In previous studies, silver 

nanoparticles were tested for antimicrobial 

activity against methicillin-resistant 

Staphylococcus epidermidis, Streptococcus 

pyogenes, Salmonella typhi and Klebsiella 

pneumonia [35], Escherichia coli [17] and 

Citrobacter sp. [36]. As a result, 

nanoparticles were found to be effective in 

destroying them. In this study, it was found 

that nanoparticles were produced in the 

highest quantity at pH 7. In contrast, silver 

nanoparticles were not produced at pH 2 or 

9 when pH was tested.   There is evidence 

that the mechanism of producing 

nanoparticles is dependent on an enzyme, 

and enzymes are sensitive to pH 

fluctuations. In the synthesis carried out by 

Birla et al. [37], using Fusarium 

oxysporum, maximum nanoparticle 

production was observed between pH 9 and 

11, with lower production occurring at pH 7 

and aggregate formation occurring between 

pH 3 and 5. It has been noted, however, that 

Husseiny et al. [38] found a decrease in 

nanoparticle synthesis rate as pH increased, 

suggesting that reductases that are 

responsible for synthesis are less active at 

higher pH levels.  The decrease in the 

efficacy of the nanoparticles produced 

against MRSA could also be attributed to 

the sensitivity to pH. The mode of 

antibacterial activity of the silver 

nanoparticles is thought to be bactericidal as 

there was no growth from zones of clearing 

indicating that the organisms had been 

killed as against the growth observed in the 

region where there was no clearing. The 

MIC and MBC of the AgNps were both 

found to be 5 mg/ml, which was similar to a 



Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava 

Volume XXI, Issue 2 – 2022 

 

 

Jane NSOFOR, Imade Yolanda NSA, Busayo Tosin AKINYEMI, Adewale Kayode OGUNYEMI, Matthew Olusoji ILORI, Microbial 

Generation of Silver Nanoparticles by Synthesizing Enterococcus feacalis strain MI103, Food and Environment Safety, 

Volume XXI, Issue 2 – 2022, pag. 143 –  151
 

150 

study by Krishnan et al. [ 39].  

4. Conclusion 

These results confirm that Enterococcus 

faecalis synthesized silver nanoparticles are 

bactericidal and are effective against 

antibiotic-resistant pathogens, thus 

providing a more efficient alternative to 

antibiotics.  

 

5. Acknowledgments  
 

The authors are indebted to Mr. James 

Ugah, a Technologist of Department of 

Microbiology, University of Lagos, Akoka, 

Lagos, Nigeria for his technical assistance 

during the course of the work. Also, we 

thank, Mr. Olanewaju Gabriel of the 

Electron Microscopy and Bio-Imaging 

laboratory, Mechanical Engineering of 

Covenant for his assistance in preparing the 

scanning electron micrographs of 

Enterococcus faecalis strain MI103.  

 

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Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava 

Volume XXI, Issue 2 – 2022 

 

 

Jane NSOFOR, Imade Yolanda NSA, Busayo Tosin AKINYEMI, Adewale Kayode OGUNYEMI, Matthew Olusoji ILORI, Microbial 

Generation of Silver Nanoparticles by Synthesizing Enterococcus feacalis strain MI103, Food and Environment Safety, 

Volume XXI, Issue 2 – 2022, pag. 143 –  151
 

151 

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	1. Introduction
	The development of antibiotic resistance has posed a significant threat, first to health and wellness and then to food security globally.  As a result of increasing abuse of antibiotics in health and industrial use, antibiotic resistance has significa...