Keywords Cellulolytic enzymes · Lignocelluloses · Process parameters · Solid-state
fermentation
3.1 Introduction
The rising of energy requirement and ecological evils reasoned by utilization of
nonrenewable fossil fuels, it has become a burning need to set up substitute energy
sources. Bioethanol generation by cellulosic substrates is anticipated as an option for
sustainable reserve for renewable fuel, which can alleviate the pressure of energy
calamity, and also assist to decrease greenhouse gas discharge (Pervez et al. 2014).
Lignocellulosic residues contain cellulose; hemicellulose and lignin bound each
other in a composite structure. Attributable to complex structure of the cellulose is
in fact challenging to microbial and enzymatic activity. Cellulose is a most copious,
renewable biopolymer, and is a cheap energy source (Zhang et al. 2009). However,
utilization of this natural biopolymer for production of useful materials through
saccharification process primarily relies on the action of cellulolytic enzymes and
also the cost of cellulase enzyme. The high cost of cellulases is the major hurdle for
profit-orientation of biomass, biorefineries (Zhang et al. 2006; Zhu et al. 2009).
Moreover, production of bioenergy and its products from cheap renewable lignocellulosic biomass would bring gain to local financial system, environment, and
public energy security (Zhang 2008). The booming strategy is to enhance the
cellulolytic enzymes production by using hyper cellulase-producing strains or
locally existing cheap raw material and optimizing culture conditions. Nevertheless,
the factors affecting lignocellulose-degrading enzyme knowledge are indispensable
for understanding the optimal conditions that take place in unique circumstances.
This chapter primarily emphasizes on factors affecting cellulolytic enzymes production in SSF from fungal sources.
3.2 Cellulose
Cellulose is a widespread polymer of plant cell walls that was first documented by
“Anselm Payen” in 1838. It happens in nearly pure form in cotton fiber and in
mixture by other substances, including lignin and hemicelluloses, in forest biomass,
plant leaves, and stalks. It was accepted that cellulose is a polymer that consists of
repeating units of glucose, a simple sugar. They detached from connected plant
substances that take place in mixture with cellulose by dissolving them in concentrated sodium hydroxide. They referred undissolved remains as an α-cellulose. The
soluble materials (referred as β-cellulose and γ-cellulose) were afterward shown not
to be celluloses, but rather, comparatively simple sugars and other carbohydrates.
The α-cellulose of Cross and Bevan is what is frequently meant when the name
“cellulose” is applied at present.
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M. Subhosh Chandra et al.
fermentation
3.1 Introduction
The rising of energy requirement and ecological evils reasoned by utilization of
nonrenewable fossil fuels, it has become a burning need to set up substitute energy
sources. Bioethanol generation by cellulosic substrates is anticipated as an option for
sustainable reserve for renewable fuel, which can alleviate the pressure of energy
calamity, and also assist to decrease greenhouse gas discharge (Pervez et al. 2014).
Lignocellulosic residues contain cellulose; hemicellulose and lignin bound each
other in a composite structure. Attributable to complex structure of the cellulose is
in fact challenging to microbial and enzymatic activity. Cellulose is a most copious,
renewable biopolymer, and is a cheap energy source (Zhang et al. 2009). However,
utilization of this natural biopolymer for production of useful materials through
saccharification process primarily relies on the action of cellulolytic enzymes and
also the cost of cellulase enzyme. The high cost of cellulases is the major hurdle for
profit-orientation of biomass, biorefineries (Zhang et al. 2006; Zhu et al. 2009).
Moreover, production of bioenergy and its products from cheap renewable lignocellulosic biomass would bring gain to local financial system, environment, and
public energy security (Zhang 2008). The booming strategy is to enhance the
cellulolytic enzymes production by using hyper cellulase-producing strains or
locally existing cheap raw material and optimizing culture conditions. Nevertheless,
the factors affecting lignocellulose-degrading enzyme knowledge are indispensable
for understanding the optimal conditions that take place in unique circumstances.
This chapter primarily emphasizes on factors affecting cellulolytic enzymes production in SSF from fungal sources.
3.2 Cellulose
Cellulose is a widespread polymer of plant cell walls that was first documented by
“Anselm Payen” in 1838. It happens in nearly pure form in cotton fiber and in
mixture by other substances, including lignin and hemicelluloses, in forest biomass,
plant leaves, and stalks. It was accepted that cellulose is a polymer that consists of
repeating units of glucose, a simple sugar. They detached from connected plant
substances that take place in mixture with cellulose by dissolving them in concentrated sodium hydroxide. They referred undissolved remains as an α-cellulose. The
soluble materials (referred as β-cellulose and γ-cellulose) were afterward shown not
to be celluloses, but rather, comparatively simple sugars and other carbohydrates.
The α-cellulose of Cross and Bevan is what is frequently meant when the name
“cellulose” is applied at present.
74
M. Subhosh Chandra et al.