346
N. B. Raj et al.
Fig. 1 Synthesis of nanoparticles using different substrates and effect of different factors (adapted
from Ali et al. 2020)
reduced by the action of enzymes present on cell wall, in the cytoplasm or in cell
filtrate, leading to NPs synthesis (Mukherjee et al. 2002).
2.1.1 Mechanism of Synthesis of AgNPs Using Fungi
In general, when fungi experience various exogenous stress such as exposure to toxic
compounds, temperature variations, pressure, nutrient depletion among others, they
produce a wide array of biological compounds and enzymes as defense mechanism.
After a fungus is exposed to toxic metal ions, it is reduced to non-toxic metallic solid
NPs by the action of various extracellular enzymes and metabolites (Vahabi et al.
2011; Durán et al. 2011a, b; Ingle et al. 2008; Mukherjee et al. 2008). First report
on synthesis of microbial-based AgNPs was documented in Fusarium oxysporum
(Ahmad et al. 2003a, b). Growing body of evidences suggests that, mycosynthesis of
AgNPs has not yet been completely understood. Various parameters such as nature of
fungus, temperature, pH, capping agents and nature of metal ions determine the size
and shape of the nanoparticles (Khandel and Shahi 2018; Lee and Jun 2019). The
probable steps involved in the mycosynthesis of AgNPs are enumerated as follows:
N. B. Raj et al.
Fig. 1 Synthesis of nanoparticles using different substrates and effect of different factors (adapted
from Ali et al. 2020)
reduced by the action of enzymes present on cell wall, in the cytoplasm or in cell
filtrate, leading to NPs synthesis (Mukherjee et al. 2002).
2.1.1 Mechanism of Synthesis of AgNPs Using Fungi
In general, when fungi experience various exogenous stress such as exposure to toxic
compounds, temperature variations, pressure, nutrient depletion among others, they
produce a wide array of biological compounds and enzymes as defense mechanism.
After a fungus is exposed to toxic metal ions, it is reduced to non-toxic metallic solid
NPs by the action of various extracellular enzymes and metabolites (Vahabi et al.
2011; Durán et al. 2011a, b; Ingle et al. 2008; Mukherjee et al. 2008). First report
on synthesis of microbial-based AgNPs was documented in Fusarium oxysporum
(Ahmad et al. 2003a, b). Growing body of evidences suggests that, mycosynthesis of
AgNPs has not yet been completely understood. Various parameters such as nature of
fungus, temperature, pH, capping agents and nature of metal ions determine the size
and shape of the nanoparticles (Khandel and Shahi 2018; Lee and Jun 2019). The
probable steps involved in the mycosynthesis of AgNPs are enumerated as follows: