Application of Microbial-Synthesized Nanoparticles …
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using biological systems. Among microorganisms, bacteria are known to synthesize nanoparticles both intracellularly and extracellularly. To date, several types of
nanoparticles such as gold, silver, silver–gold alloy, zirconia, cadmium, and many
more have been synthesized using different bacteria (Mubarak et al. 2012; Asmathunisha and Kathiresan 2013; Ojo et al. 2016; Oladipo et al. 2017; Debnath et al.
2020). Recent advances demonstrate several fields of application for these nanoparticles, e.g., pharmaceutical (Yadav et al. 2011), bioremediation (Debnath et al. 2020),
anticancer activity (Ebrahimzadeh et al. 2020), tumor targeting (Park et al. 2008) as
well as anticoagulant and thrombolytic activities (Lateef et al. 2018a, b; Elegbede
and Lateef 2019). For instance, Debnath et al. (2020) has shown the applicability
of zirconia nanoparticles (ZrO 2 NPs) produced by Pseudomonas aeruginosa in the
removal of tetracycline by adsorption from contaminated waste water. From that,
they conducted the assays varying different process parameter such as contact time,
pH and ZrO 2 NPs concentration in order to establish the most suitable conditions to
achieve a higher efficiency. The aforementioned variables presented optimum conditions at pH 6.0, ZrO 2 at 1.2 g/L and contact time of 30 min; these combined removed
up to 98% of total target.
In alignment to the strategy of controlling microbial availability to prevent infectious diseases, Jayaseelan et al. (2012) reported the use of non-toxic ZnO nanoparticles synthesized by Aeromonas hydrophila against pathogenic bacteria and fungi.
A series of various microorganisms were tested to examine the antimicrobial and
antifungal activity through the method of well diffusion and minimum inhibitory
concentration, and controls were subjected to antibiotics as a comparison. The significant zone of inhibition was found in the case of P. aeruginosa and A. flavus
along with maximum measured halo of 22 and 19 mm, respectively, with minimum
inhibitory concentration of 2.9 µg/ml was achieved. In brief, advantageous findings
of A. hydrophila nanoparticle synthesis pathway enabled scientists to perform rapid
ZnONPs biosynthesis at cost-effective and feasible conditions. Still, the phenomenon
which elucidates such antimicrobial activity is associated to the surface–volume
ratio, size, and shape of nanoparticles, in such manner that the microbial membrane
permeability is modified by introducing gaps or pits therein hindering respiratory
metabolism that leads to apoptosis of the cells (Baker and Satish 2015). In the case
of gram-positive bacteria as it naturally has a thicker layer of peptidoglycan cell
wall which confers overwhelming resistance toward many biochemicals, it has been
shown that biosynthesized gold nanoparticles (AuNPs) also present a capability of
acting as an inhibitor to its cellular survival, thus offering an alternative over the use
of antibiotics (Menon et al. 2017).
In a combination approach, silver and gold nanoparticles were biosynthesized by
Sporosarcina koreensis DC4. Particularly, with respect to enhancement of antimicrobial growth, activities of several commercial antibiotics improved by approximately
five-fold in the presence of silver nanoparticles (AgNPs) against significantly resistant microorganisms such as E. coli, V. parahaemolyticus and S. enterica (Singh
et al. 2016). Similarly, Lateef et al. (2015a) reported improvement of 7.4–142.9%
for some antibiotics against bacteria due to synergistic effect with AgNPs biosynthesized by Bacillus safensis. The AgNPs also showed anti-candida, anticoagulant,
401
using biological systems. Among microorganisms, bacteria are known to synthesize nanoparticles both intracellularly and extracellularly. To date, several types of
nanoparticles such as gold, silver, silver–gold alloy, zirconia, cadmium, and many
more have been synthesized using different bacteria (Mubarak et al. 2012; Asmathunisha and Kathiresan 2013; Ojo et al. 2016; Oladipo et al. 2017; Debnath et al.
2020). Recent advances demonstrate several fields of application for these nanoparticles, e.g., pharmaceutical (Yadav et al. 2011), bioremediation (Debnath et al. 2020),
anticancer activity (Ebrahimzadeh et al. 2020), tumor targeting (Park et al. 2008) as
well as anticoagulant and thrombolytic activities (Lateef et al. 2018a, b; Elegbede
and Lateef 2019). For instance, Debnath et al. (2020) has shown the applicability
of zirconia nanoparticles (ZrO 2 NPs) produced by Pseudomonas aeruginosa in the
removal of tetracycline by adsorption from contaminated waste water. From that,
they conducted the assays varying different process parameter such as contact time,
pH and ZrO 2 NPs concentration in order to establish the most suitable conditions to
achieve a higher efficiency. The aforementioned variables presented optimum conditions at pH 6.0, ZrO 2 at 1.2 g/L and contact time of 30 min; these combined removed
up to 98% of total target.
In alignment to the strategy of controlling microbial availability to prevent infectious diseases, Jayaseelan et al. (2012) reported the use of non-toxic ZnO nanoparticles synthesized by Aeromonas hydrophila against pathogenic bacteria and fungi.
A series of various microorganisms were tested to examine the antimicrobial and
antifungal activity through the method of well diffusion and minimum inhibitory
concentration, and controls were subjected to antibiotics as a comparison. The significant zone of inhibition was found in the case of P. aeruginosa and A. flavus
along with maximum measured halo of 22 and 19 mm, respectively, with minimum
inhibitory concentration of 2.9 µg/ml was achieved. In brief, advantageous findings
of A. hydrophila nanoparticle synthesis pathway enabled scientists to perform rapid
ZnONPs biosynthesis at cost-effective and feasible conditions. Still, the phenomenon
which elucidates such antimicrobial activity is associated to the surface–volume
ratio, size, and shape of nanoparticles, in such manner that the microbial membrane
permeability is modified by introducing gaps or pits therein hindering respiratory
metabolism that leads to apoptosis of the cells (Baker and Satish 2015). In the case
of gram-positive bacteria as it naturally has a thicker layer of peptidoglycan cell
wall which confers overwhelming resistance toward many biochemicals, it has been
shown that biosynthesized gold nanoparticles (AuNPs) also present a capability of
acting as an inhibitor to its cellular survival, thus offering an alternative over the use
of antibiotics (Menon et al. 2017).
In a combination approach, silver and gold nanoparticles were biosynthesized by
Sporosarcina koreensis DC4. Particularly, with respect to enhancement of antimicrobial growth, activities of several commercial antibiotics improved by approximately
five-fold in the presence of silver nanoparticles (AgNPs) against significantly resistant microorganisms such as E. coli, V. parahaemolyticus and S. enterica (Singh
et al. 2016). Similarly, Lateef et al. (2015a) reported improvement of 7.4–142.9%
for some antibiotics against bacteria due to synergistic effect with AgNPs biosynthesized by Bacillus safensis. The AgNPs also showed anti-candida, anticoagulant,