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J. A. Elegbede and A. Lateef
hand, SSF involves culturing microorganisms on solid substrates with slightly raised
moisture content with total or near deficiency of free water. This is described as a
fermentation process on semisolid or solid substrate or such that occurs on a nutritionally static solid support. SSF presents some benefits such as access to nutrients
for microorganisms and high purity of product. Moreover, immobilization of cells
is the binding of cells or cellular inclusion on a distinct solid phase which permits
exchange of substrates, product, in addition to inhibitors, etc. and simultaneously
separates the catalytic cell biomass from the bulk phase containing substrates and
products (Sabu 2003).
2.3 Applications of Microbial Enzymes in the Synthesis
of Nanomterials
The compass of biosynthesis of nanomaterials is on a continuous expansion in recent
times by reason of the vast accessibility of bioresources (Ojo et al. 2016; Oladipo
et al. 2017a; Adelere and Lateef 2016; Lateef et al. 2016e; Elegebede and Lateef
2020). Interests in applications of biological systems including microorganisms as
cell factories in fabrication of nanoparticles having novel biological activities keep
increasing dramatically. Although there are a lot of other biomaterials employed
in nanobiotechnology, plants and microorganisms (fungi and bacteria) are at the
first line of investigations in nanoparticles biosynthesis via both extracellular and
intracellular routes (Ogi et al. 2010; Pandian et al. 2010). The biosynthetic processes
are less labor-intensive, nontoxic, low-cost technique. Diverse types of biogenic
nanomaterials including cadmium sulfide, zinc, copper, titanium, gold, magnesium,
silver and platinum have been biosynthesized using biological resources (GholamiShabani et al. 2015).
Microorganisms such as fungi, bacteria and algae and their metabolites contribute
a noteworthy function in nanoparticles biosynthesis. Enzymes, extracellular polysaccharides, DNA and rhamnolipids are all involved in biosynthesis of nanoparticles
which would lead to the fabrication of polydispersed nanoparticles as a result of the
attendance of multiple organic constituents in cell-free extract or cell suspension.
Proteins mostly cover the face of such bionanoparticles and may confer stability to it
(Durán et al. 2011; Gholami-Shabani et al. 2015; Kitching et al. 2015). Also, it was
proposed that proteins, organic acids and polysaccharides released by different fungi
were capable of distinguishing different crystal shapes and growth was directed
into spherical crystals (Shedbalkar et al. 2014). Proteins and peptides which are
biomolecules that can also be established in microbial enzymes have been described
to be responsible for biosynthesis nanoparticles. The existence of peptide groups
with proteins molecules (amino acid groups) in enzymes opens up a probability of
them being directly implicated in the bioreduction of metals in the biofabrication
of nanoparticles. Functional groups indicating the occurrence of protein moieties
have been implicated in various studies in the synthesis of nanoparticles (Adelere
J. A. Elegbede and A. Lateef
hand, SSF involves culturing microorganisms on solid substrates with slightly raised
moisture content with total or near deficiency of free water. This is described as a
fermentation process on semisolid or solid substrate or such that occurs on a nutritionally static solid support. SSF presents some benefits such as access to nutrients
for microorganisms and high purity of product. Moreover, immobilization of cells
is the binding of cells or cellular inclusion on a distinct solid phase which permits
exchange of substrates, product, in addition to inhibitors, etc. and simultaneously
separates the catalytic cell biomass from the bulk phase containing substrates and
products (Sabu 2003).
2.3 Applications of Microbial Enzymes in the Synthesis
of Nanomterials
The compass of biosynthesis of nanomaterials is on a continuous expansion in recent
times by reason of the vast accessibility of bioresources (Ojo et al. 2016; Oladipo
et al. 2017a; Adelere and Lateef 2016; Lateef et al. 2016e; Elegebede and Lateef
2020). Interests in applications of biological systems including microorganisms as
cell factories in fabrication of nanoparticles having novel biological activities keep
increasing dramatically. Although there are a lot of other biomaterials employed
in nanobiotechnology, plants and microorganisms (fungi and bacteria) are at the
first line of investigations in nanoparticles biosynthesis via both extracellular and
intracellular routes (Ogi et al. 2010; Pandian et al. 2010). The biosynthetic processes
are less labor-intensive, nontoxic, low-cost technique. Diverse types of biogenic
nanomaterials including cadmium sulfide, zinc, copper, titanium, gold, magnesium,
silver and platinum have been biosynthesized using biological resources (GholamiShabani et al. 2015).
Microorganisms such as fungi, bacteria and algae and their metabolites contribute
a noteworthy function in nanoparticles biosynthesis. Enzymes, extracellular polysaccharides, DNA and rhamnolipids are all involved in biosynthesis of nanoparticles
which would lead to the fabrication of polydispersed nanoparticles as a result of the
attendance of multiple organic constituents in cell-free extract or cell suspension.
Proteins mostly cover the face of such bionanoparticles and may confer stability to it
(Durán et al. 2011; Gholami-Shabani et al. 2015; Kitching et al. 2015). Also, it was
proposed that proteins, organic acids and polysaccharides released by different fungi
were capable of distinguishing different crystal shapes and growth was directed
into spherical crystals (Shedbalkar et al. 2014). Proteins and peptides which are
biomolecules that can also be established in microbial enzymes have been described
to be responsible for biosynthesis nanoparticles. The existence of peptide groups
with proteins molecules (amino acid groups) in enzymes opens up a probability of
them being directly implicated in the bioreduction of metals in the biofabrication
of nanoparticles. Functional groups indicating the occurrence of protein moieties
have been implicated in various studies in the synthesis of nanoparticles (Adelere