200
J. A. Elegbede and A. Lateef
(2014) described the environmental benign synthesis and characterization of AuNPs
using purified amylase from A. oryzae. The SPR band at 525 nm confirmed the
existence of AuNPs, which were revealed to be spherically structured with sizes
varying from 2–20 nm via TEM microscopy. The nanoparticles were examined for
the chemocatalysis of p-nitrophenol and p-nitroaniline in aqueous solutions, and the
results obtained could be applied in the biomanagement of nitroaromatic pollutants
in solution. Also, purified fibrinolytic enzyme obtained from Bacillus cereus NK1
was reported by Deepak et al. (2011) to mediate the biogenic synthesis of AuNPs
within 60 h which was considerably reduced to 12 h upon the addition of NaOH
solution. The spherical-shaped AuNPs obtained were revealed to be crystalline in
nature with an approximate size of 20 nm.
Moreover, Babu Maddinedi et al. (2015) reported the efficiency of diastase as both
reducing and stabilizing mediator for the size controlled biosynthesis of AuNPs, and
it was observed that varying the quantity of the diastase used can successfully tune
the size variation of the AuNPs. Also, the existence of thiol groups of enzyme was
proposed to play foremost role in the shape and size tuning. Cytotoxicity study
carried out in vitro via MTT assay on A549 and HCT116 cancer cells revealed
that cytotoxicity of AuNPs relies on its dose and size. Gupta et al. (2015) reported
the effect of combined interaction of keratinase and reductase for simplistic biogenic
synthesis of AuNPs. Keratinase and disulfide reductase generated by Bacillus subtilis
RSE163 in chicken feather degradation was utilized to reduce Au
3+ to synthesize
AuNPs. The AuNPs were absorbed around 540 nm under the UV–Vis spectrum
attributed to SPR absorbance of gold. HRTEM showed that the AuNPs are well
dispersed, spherically shaped with sizes varying from 50–80 nm. Interaction with
Escherichia coli ATCC 11,103 established the nontoxic nature of biogenic AuNPs,
where the growth rate improvement of E. coli observed in the log phase indicated their
nontoxicity. Also, Gholami-Shabani et al. (2015) biosynthesized AuNPs utilizing
cell-free purified α-NADPH-dependent sulfite reductase produced by E. coli. The
AuNPs were described to be spherically structured with an approximate size of 10 nm.
Also, the biosynthesized AuNPs demonstrated good antifungal activity against some
human fungal pathogens.
2.5.3 Other Metal-Based Nanoparticles Synthesized Using Microbial
Enzymes
Selenium nanoparticles have been described to be biosynthesized using enzymes
from microbial sources. Wadhwani et al. (2018) reported the biogenic synthesis
of SeNPs using purified lignin peroxidase produced by Acinetobacter sp. SW30.
The biosynthesized SeNPs were revealed to be amorphous and crystalline with
approximate size of 100 ± 10 nm. NADH, NADH-dependent reductases, disulfide
reductase and fumarate reductase were reported to play noteworthy roles in biosynthesis of SeNPs involving bacterial strain JS-11 (Dwivedi et al. 2013). Also, the
environmental-friendly synthesis of seleniun nanoparticles (SeNPs) was reported by
Dizaj et al. (2013) using purified α-amylase produced by B. methylotrophicus which
J. A. Elegbede and A. Lateef
(2014) described the environmental benign synthesis and characterization of AuNPs
using purified amylase from A. oryzae. The SPR band at 525 nm confirmed the
existence of AuNPs, which were revealed to be spherically structured with sizes
varying from 2–20 nm via TEM microscopy. The nanoparticles were examined for
the chemocatalysis of p-nitrophenol and p-nitroaniline in aqueous solutions, and the
results obtained could be applied in the biomanagement of nitroaromatic pollutants
in solution. Also, purified fibrinolytic enzyme obtained from Bacillus cereus NK1
was reported by Deepak et al. (2011) to mediate the biogenic synthesis of AuNPs
within 60 h which was considerably reduced to 12 h upon the addition of NaOH
solution. The spherical-shaped AuNPs obtained were revealed to be crystalline in
nature with an approximate size of 20 nm.
Moreover, Babu Maddinedi et al. (2015) reported the efficiency of diastase as both
reducing and stabilizing mediator for the size controlled biosynthesis of AuNPs, and
it was observed that varying the quantity of the diastase used can successfully tune
the size variation of the AuNPs. Also, the existence of thiol groups of enzyme was
proposed to play foremost role in the shape and size tuning. Cytotoxicity study
carried out in vitro via MTT assay on A549 and HCT116 cancer cells revealed
that cytotoxicity of AuNPs relies on its dose and size. Gupta et al. (2015) reported
the effect of combined interaction of keratinase and reductase for simplistic biogenic
synthesis of AuNPs. Keratinase and disulfide reductase generated by Bacillus subtilis
RSE163 in chicken feather degradation was utilized to reduce Au
3+ to synthesize
AuNPs. The AuNPs were absorbed around 540 nm under the UV–Vis spectrum
attributed to SPR absorbance of gold. HRTEM showed that the AuNPs are well
dispersed, spherically shaped with sizes varying from 50–80 nm. Interaction with
Escherichia coli ATCC 11,103 established the nontoxic nature of biogenic AuNPs,
where the growth rate improvement of E. coli observed in the log phase indicated their
nontoxicity. Also, Gholami-Shabani et al. (2015) biosynthesized AuNPs utilizing
cell-free purified α-NADPH-dependent sulfite reductase produced by E. coli. The
AuNPs were described to be spherically structured with an approximate size of 10 nm.
Also, the biosynthesized AuNPs demonstrated good antifungal activity against some
human fungal pathogens.
2.5.3 Other Metal-Based Nanoparticles Synthesized Using Microbial
Enzymes
Selenium nanoparticles have been described to be biosynthesized using enzymes
from microbial sources. Wadhwani et al. (2018) reported the biogenic synthesis
of SeNPs using purified lignin peroxidase produced by Acinetobacter sp. SW30.
The biosynthesized SeNPs were revealed to be amorphous and crystalline with
approximate size of 100 ± 10 nm. NADH, NADH-dependent reductases, disulfide
reductase and fumarate reductase were reported to play noteworthy roles in biosynthesis of SeNPs involving bacterial strain JS-11 (Dwivedi et al. 2013). Also, the
environmental-friendly synthesis of seleniun nanoparticles (SeNPs) was reported by
Dizaj et al. (2013) using purified α-amylase produced by B. methylotrophicus which