(pentoses) were utilized by few native strains to produce ethanol at relatively low
yields.
The basic five stages of this process are:
1. Pretreatment step – makes the raw material amenable to hydrolysis
2. Hydrolysis step – to break down the cellulose present in solid fraction into sugars
3. Collection of liquid hydrolyzate and detection of inhibitory compounds such as
furfurals, hydroxymethylfurfural (HMF), and acetic acid
4. Fermentation of the five and six carbon containing sugar solution
5. Distillation and dehydration step to produce absolute ethanol
3 Different Pretreatment Techniques Employed on SCT
The pretreatment is the most crucial step in biomass conversion as it possesses a
huge impact on the efficiency of bioethanol production. Lignocellulosic biomass
mainly consists of densely packed cellulose and hemicelluloses along with lignin
which serves plant for performing several functions [13]. The aim of the
pretreatment is to make cellulose more accessible to the enzymes for the conversion
into fermentable sugars which can be done by disrupting the recalcitrant lignin
structures using different pretreatment techniques. The removal of lignin mainly
depends on the type of pretreatment employed and the optimum conditions
Fig. 2 Size reduction process employed prior to pretreatment step
92
S. Niju and M. Swathika
yields.
The basic five stages of this process are:
1. Pretreatment step – makes the raw material amenable to hydrolysis
2. Hydrolysis step – to break down the cellulose present in solid fraction into sugars
3. Collection of liquid hydrolyzate and detection of inhibitory compounds such as
furfurals, hydroxymethylfurfural (HMF), and acetic acid
4. Fermentation of the five and six carbon containing sugar solution
5. Distillation and dehydration step to produce absolute ethanol
3 Different Pretreatment Techniques Employed on SCT
The pretreatment is the most crucial step in biomass conversion as it possesses a
huge impact on the efficiency of bioethanol production. Lignocellulosic biomass
mainly consists of densely packed cellulose and hemicelluloses along with lignin
which serves plant for performing several functions [13]. The aim of the
pretreatment is to make cellulose more accessible to the enzymes for the conversion
into fermentable sugars which can be done by disrupting the recalcitrant lignin
structures using different pretreatment techniques. The removal of lignin mainly
depends on the type of pretreatment employed and the optimum conditions
Fig. 2 Size reduction process employed prior to pretreatment step
92
S. Niju and M. Swathika