Environmental Nanobiotechnology: Microbial-Mediated …
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of pesticides and using of low quality waters for irrigation in many places (AbouShanab et al. 2012; Hoballah et al. 2014; Saber et al. 2014). Monitoring of the
pollution levels, find the ideal treatment to remove, detoxify, or reduce their negative
impacts on environment considers as the minimum liability towards the environment.
Pollution prevention from beginning will be more sustainable for humans and their
environments as well. In addition, due to the depletion and limitations of many
resources, it is an emergency demand to reserve and keep the limited resources as
much as possible for next generations. In this regards, new technologies should be
environmental friendly to prevent the destruction of the environment and keep it
sustainable. Traditional technologies also should be revised and improved to fulfill
the ethics for clean and sustainable environment.
3 Nanomaterials and Microbial Synthesis Procedures
The development of environmental-safe and ecofriendly technologies for nanomaterials synthesis and production superior substances is considered importance
to increase their biological applications. The microbial-synthesized nanoparticles
are distributed in a wide spectrum of potential areas from wastewater treatment,
biofuel production, biofertilizers providing to food industry improvement (Li et al.
2011; Darwesh et al. 2018b). The nanomaterials are microbial-synthesized when the
microbes targeted ions from their environment and convert these ions into element
metal via enzymes system. Various microbes have different mechanisms for nanomaterials formation. Though, nanomaterials are usually manufactured by trapping the
metal ions on the surface or inside the microbial cells. The trapped ions are reduced
to nanosize by enzymes system. Generally, microorganisms influence the mineral
formation in two ways. The first one is to modify the composition to become supersaturated or more supersaturated than it previously was with respect to a specific
phase. A second means by which microorganisms can impact mineral formation is
through the production of organic polymers, which can impact nucleation by favoring
or inhibiting the stabilization of the very first mineral seeds (Fig. 1).
The NADH and NADH-dependent nitrate reductase enzymes are reported as
important factors in microbial synthesis of metal nanomaterials. Nitrate reductase
enzyme might be responsible for the bio-reduction of Ag
+ to Ag
0 and the subsequent formation of silver nanoparticles (Darwesh et al. 2019a). Microbial enzymes
such as laccase, keratinase and xylanase among others have been used to synthesize
metallic nanoparticles for different applications (Lateef et al. 2015a; Adelere and
Lateef 2016; Lateef and Adeeyo 2015; Elegbede et al. 2020). Microorganisms have
many metal resistance gene clusters allowing cell detoxification through a number of
mechanisms like complexation, reductive precipitation or efflux. The metallophilic
bacteria survive and thrive in environments containing high concentrations of heavy
metals like mine waste rock piles, naturally mineralized zones and efflux streams of
metal processing plants (Nies 1999). Many microbes were reported for nanomaterials manufacturing like genus of Bacillus, Enterococcus, Pseudomonas, Fusarium,
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of pesticides and using of low quality waters for irrigation in many places (AbouShanab et al. 2012; Hoballah et al. 2014; Saber et al. 2014). Monitoring of the
pollution levels, find the ideal treatment to remove, detoxify, or reduce their negative
impacts on environment considers as the minimum liability towards the environment.
Pollution prevention from beginning will be more sustainable for humans and their
environments as well. In addition, due to the depletion and limitations of many
resources, it is an emergency demand to reserve and keep the limited resources as
much as possible for next generations. In this regards, new technologies should be
environmental friendly to prevent the destruction of the environment and keep it
sustainable. Traditional technologies also should be revised and improved to fulfill
the ethics for clean and sustainable environment.
3 Nanomaterials and Microbial Synthesis Procedures
The development of environmental-safe and ecofriendly technologies for nanomaterials synthesis and production superior substances is considered importance
to increase their biological applications. The microbial-synthesized nanoparticles
are distributed in a wide spectrum of potential areas from wastewater treatment,
biofuel production, biofertilizers providing to food industry improvement (Li et al.
2011; Darwesh et al. 2018b). The nanomaterials are microbial-synthesized when the
microbes targeted ions from their environment and convert these ions into element
metal via enzymes system. Various microbes have different mechanisms for nanomaterials formation. Though, nanomaterials are usually manufactured by trapping the
metal ions on the surface or inside the microbial cells. The trapped ions are reduced
to nanosize by enzymes system. Generally, microorganisms influence the mineral
formation in two ways. The first one is to modify the composition to become supersaturated or more supersaturated than it previously was with respect to a specific
phase. A second means by which microorganisms can impact mineral formation is
through the production of organic polymers, which can impact nucleation by favoring
or inhibiting the stabilization of the very first mineral seeds (Fig. 1).
The NADH and NADH-dependent nitrate reductase enzymes are reported as
important factors in microbial synthesis of metal nanomaterials. Nitrate reductase
enzyme might be responsible for the bio-reduction of Ag
+ to Ag
0 and the subsequent formation of silver nanoparticles (Darwesh et al. 2019a). Microbial enzymes
such as laccase, keratinase and xylanase among others have been used to synthesize
metallic nanoparticles for different applications (Lateef et al. 2015a; Adelere and
Lateef 2016; Lateef and Adeeyo 2015; Elegbede et al. 2020). Microorganisms have
many metal resistance gene clusters allowing cell detoxification through a number of
mechanisms like complexation, reductive precipitation or efflux. The metallophilic
bacteria survive and thrive in environments containing high concentrations of heavy
metals like mine waste rock piles, naturally mineralized zones and efflux streams of
metal processing plants (Nies 1999). Many microbes were reported for nanomaterials manufacturing like genus of Bacillus, Enterococcus, Pseudomonas, Fusarium,