arabinofuranosidase, acetyl xylan esterase, and ferulic acid esterase are the enzymes
which degrade the xylan components. All enzymes act in the sequential manner to
degrade the hemicellulose to xylose (Shallom and Shoham 2003; Satyanarayana
et al. 2019).
7.2.2 Exopolysaccharides
Various biotechnological applications are mainly focused on the natural and biopolymers which have huge demand in the market. Various fungi produce the
extracellular polymeric substances such as exopolysaccharides (EPS) which have
huge demand in recent times. Various types of polysaccharides are produced by
plants which are cellulose, starch, and pectin. Likewise, algae produce the agar,
alginate, and carrageenan type of polysaccharides which have huge biotechnology
demand. Bacteria also produce the dextran, alginate, gellan, xanthan gum, and
pullulan which are commonly used as food additives for their gelling, stabilizing,
or thickening properties. Polysaccharides comprise higher capacity for the chelation
and entrapment of hazardous contaminants (Kumar et al. 2007). Increasing interest
to resolve the environmental issues and its production using green or environmental
friendly procedures leads to the production of such substances that are mainly
important for the global market for microbial products to about 250 billion US
dollars by 2016. This carbohydrate product is the metabolite which secrete by the
fungi on the cell surface which plays a critical role in various industries. EPS gained
attention in the pharmaceutic industries due to their involvement in various biological mechanisms such as signal transduction, adhesion, infection, and immune
response (Sutherland 2002; Kumar et al. 2007). Microbial polysaccharides are the
polymer which comprises higher molecular weight. It is generally presented at
lipopolysaccharides or capsular polysaccharides (Taylor and Roberts 2005).
An important distinction of polysaccharide is based on their charge properties;
they may be naturally anionic and neutral. Microbial EPS like xanthan,
phosphomannan and alginate belong to anionic group while EPS like levan,
scleroglucan, pullulan, and dextran belong to neutral group. Some polysaccharides
have anionic properties, and they contain acidic groups, such as carboxyl, phosphate,
or sulfate. The diversity of various EPS produced by microorganisms is often
stressed. At present, a considerable number of bacteria, lactic acid bacteria (LAB),
higher basidiomycetes, lower filamentous fungi and yeasts from different ecological
niches are known for their ability to synthesize EPS in nature as well as in laboratory
culture system. Important EPS is produced by various fungi which is shown in
Table 7.2.
Polysaccharide that comprises single glucose subunits is called as glucans
(Murray et al. 2002). These types of carbohydrates include the glycogen, cellulose,
and dextran. General formula of these polysaccharides are (C 6 H 12 O 5 ) n (Duchon
1985). Other polysaccharides called β-glucans, β-1,3-D-glucans, or β-1,4-D-glucans
are generally present in higher plants.
7 Strategies to Improve Remediation Technology Using Fungi
191
which degrade the xylan components. All enzymes act in the sequential manner to
degrade the hemicellulose to xylose (Shallom and Shoham 2003; Satyanarayana
et al. 2019).
7.2.2 Exopolysaccharides
Various biotechnological applications are mainly focused on the natural and biopolymers which have huge demand in the market. Various fungi produce the
extracellular polymeric substances such as exopolysaccharides (EPS) which have
huge demand in recent times. Various types of polysaccharides are produced by
plants which are cellulose, starch, and pectin. Likewise, algae produce the agar,
alginate, and carrageenan type of polysaccharides which have huge biotechnology
demand. Bacteria also produce the dextran, alginate, gellan, xanthan gum, and
pullulan which are commonly used as food additives for their gelling, stabilizing,
or thickening properties. Polysaccharides comprise higher capacity for the chelation
and entrapment of hazardous contaminants (Kumar et al. 2007). Increasing interest
to resolve the environmental issues and its production using green or environmental
friendly procedures leads to the production of such substances that are mainly
important for the global market for microbial products to about 250 billion US
dollars by 2016. This carbohydrate product is the metabolite which secrete by the
fungi on the cell surface which plays a critical role in various industries. EPS gained
attention in the pharmaceutic industries due to their involvement in various biological mechanisms such as signal transduction, adhesion, infection, and immune
response (Sutherland 2002; Kumar et al. 2007). Microbial polysaccharides are the
polymer which comprises higher molecular weight. It is generally presented at
lipopolysaccharides or capsular polysaccharides (Taylor and Roberts 2005).
An important distinction of polysaccharide is based on their charge properties;
they may be naturally anionic and neutral. Microbial EPS like xanthan,
phosphomannan and alginate belong to anionic group while EPS like levan,
scleroglucan, pullulan, and dextran belong to neutral group. Some polysaccharides
have anionic properties, and they contain acidic groups, such as carboxyl, phosphate,
or sulfate. The diversity of various EPS produced by microorganisms is often
stressed. At present, a considerable number of bacteria, lactic acid bacteria (LAB),
higher basidiomycetes, lower filamentous fungi and yeasts from different ecological
niches are known for their ability to synthesize EPS in nature as well as in laboratory
culture system. Important EPS is produced by various fungi which is shown in
Table 7.2.
Polysaccharide that comprises single glucose subunits is called as glucans
(Murray et al. 2002). These types of carbohydrates include the glycogen, cellulose,
and dextran. General formula of these polysaccharides are (C 6 H 12 O 5 ) n (Duchon
1985). Other polysaccharides called β-glucans, β-1,3-D-glucans, or β-1,4-D-glucans
are generally present in higher plants.
7 Strategies to Improve Remediation Technology Using Fungi
191