Microbial-Mediated Nanoparticles for Sustainable Environment …
289
green synthesis of NPs. This is due to the augmented mean generation rate and
genetic transformation potentials of the bacterial cells (Majumdar et al. 2020). The
reduction procedure of metallic ions by bacterial cells is usually a result of their effort
of defeating metallic toxicity to their cells. Secondary metabolites are also produced
in the secondary phase of the bacterial maturation phase inside the culturing media,
which act as vigorous stabilizers for NPs synthesis. The concept of stable NPs production by bacterial cells also arises from bacterial cells’ potential in active prevention of
the particle agglomeration. Microbial and specifically bacterial-driven NPs synthesis
can be technically referred to as a by-product of the resistive mechanism established
by microbial cells in response toward metals invading cell. This signifies a direct
consequence of microbial species evolution in the higher concentration ecospheric
zones. In a more specialized manner, green microbial NPs are fabricated when the
microbial organisms are grabbing target ions provided by the immediate environment and causing reduction of the metallic ions by means of enzymatic substances
produced by different cellular activities. Through this process, the toxic metallic ions
are converted to their non-toxic forms by means of the reduction to elemental forms.
In another alternative pathway of microbial NPs synthesis, there is an attachment of
the metallic ions onto the microbial cells, resulting in production of the stabilized NP
complexes, nullifying the need for extra energy requirements. In case of microbial
synthesis of NPs, the synthetic site possesses a significant position. For intracellular
procedure, there exists a transportation of ions inside microbial cell from NPs in the
presence of the enzymatic substances. But extracellular procedures are based on the
metallic ions ensnaring over microbial cells surficial level leading to the reduction
aided by microbial enzymes (Li et al. 2011; Zhang et al. 2011).
Microbial potential of metallic ions reduction and stabilization by acting as a
bio-template have been utilized for a wide range of elements for development of
NPs having well-defined structural, compositional, morphological, optical, and electrochemical aspects. Different researchers have investigated the auspiciousness of
microbial green NPs (Hulkoti and Taranath 2014; Siddiqi and Husen 2016; Prasad
et al. 2016; Gahlawat and Choudhury 2019). However, to the best of our knowledge, no review has been published signifying the role of microbial green NPs
synthesized via nano-biotechnological route in strengthening environmental sustainability by highlighting the role of green NPs in solving environmental challenges in
a sustainable manner.
Therefore, the current chapter has been compiled to signify the profound involvement of the microbially synthesized green NPs in terms of their candidacy for
becoming sustainable environmental detoxifiers. This chapter comprises of the
detailed account of microbial NPs in terms of environmental sustainability in addition to the environmental remediation carried out with these nano-biotechnological
tools. The discussion over environmental role, i.e, antimicrobial and photocatalytic
activities, played by green NPs synthesized via microbial route has been limited
to silver (AgNPs) considering the excellent behavior of AgNPs in exceeding other
NPs in terms of catalytic and antimicrobial performance. In the final portion of the
chapter, there is a brief summarization of the closing comments in terms of future
perspectives and challenges regarding microbial NPs.
289
green synthesis of NPs. This is due to the augmented mean generation rate and
genetic transformation potentials of the bacterial cells (Majumdar et al. 2020). The
reduction procedure of metallic ions by bacterial cells is usually a result of their effort
of defeating metallic toxicity to their cells. Secondary metabolites are also produced
in the secondary phase of the bacterial maturation phase inside the culturing media,
which act as vigorous stabilizers for NPs synthesis. The concept of stable NPs production by bacterial cells also arises from bacterial cells’ potential in active prevention of
the particle agglomeration. Microbial and specifically bacterial-driven NPs synthesis
can be technically referred to as a by-product of the resistive mechanism established
by microbial cells in response toward metals invading cell. This signifies a direct
consequence of microbial species evolution in the higher concentration ecospheric
zones. In a more specialized manner, green microbial NPs are fabricated when the
microbial organisms are grabbing target ions provided by the immediate environment and causing reduction of the metallic ions by means of enzymatic substances
produced by different cellular activities. Through this process, the toxic metallic ions
are converted to their non-toxic forms by means of the reduction to elemental forms.
In another alternative pathway of microbial NPs synthesis, there is an attachment of
the metallic ions onto the microbial cells, resulting in production of the stabilized NP
complexes, nullifying the need for extra energy requirements. In case of microbial
synthesis of NPs, the synthetic site possesses a significant position. For intracellular
procedure, there exists a transportation of ions inside microbial cell from NPs in the
presence of the enzymatic substances. But extracellular procedures are based on the
metallic ions ensnaring over microbial cells surficial level leading to the reduction
aided by microbial enzymes (Li et al. 2011; Zhang et al. 2011).
Microbial potential of metallic ions reduction and stabilization by acting as a
bio-template have been utilized for a wide range of elements for development of
NPs having well-defined structural, compositional, morphological, optical, and electrochemical aspects. Different researchers have investigated the auspiciousness of
microbial green NPs (Hulkoti and Taranath 2014; Siddiqi and Husen 2016; Prasad
et al. 2016; Gahlawat and Choudhury 2019). However, to the best of our knowledge, no review has been published signifying the role of microbial green NPs
synthesized via nano-biotechnological route in strengthening environmental sustainability by highlighting the role of green NPs in solving environmental challenges in
a sustainable manner.
Therefore, the current chapter has been compiled to signify the profound involvement of the microbially synthesized green NPs in terms of their candidacy for
becoming sustainable environmental detoxifiers. This chapter comprises of the
detailed account of microbial NPs in terms of environmental sustainability in addition to the environmental remediation carried out with these nano-biotechnological
tools. The discussion over environmental role, i.e, antimicrobial and photocatalytic
activities, played by green NPs synthesized via microbial route has been limited
to silver (AgNPs) considering the excellent behavior of AgNPs in exceeding other
NPs in terms of catalytic and antimicrobial performance. In the final portion of the
chapter, there is a brief summarization of the closing comments in terms of future
perspectives and challenges regarding microbial NPs.