List-of-figures_2022_Lignocellulosic-Biomass-in-Biotechnology

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List of figures
FIG. 2.1 Lignocellulose and its components (USDA Agricultural Research Service). 12
FIG. 2.2 Chemical structures of cellulose chains. Reproduced with permission 
(Lee et al., 2014). 14
FIG. 2.3 Chemical structure of hemicellulose compounds (xylan and 
glucomannan are the most existing biopolymer). Reproduced with 
permission (Lee et al., 2014). 15
FIG. 2.4 Chemical structure of lignin. Reproduced with permission 
(Lee et al., 2014). 18
FIG. 2.5 P-coumaryl-, coniferyl-, and sinapyl-alcohol: main building blocks 
of lignin. 18
FIG. 5.1 Schematic representation of the xylan polymer and xylanolytic 
enzymes system. Reproduced with permission (Beg et al., 2001). 54
FIG. 6.1 Substrate specificity of CWDEs toward the main cell wall polysaccharides. 
The cleavage sites of the major CWDEs involved in the degradation of 
lignocellulose (A), peptidoglycan (B), and chitin (C) are shown. 
(A) Arabinoxylan and homogalacturonan are reported as examples of 
hemicellulose and pectin polysaccharides, (B) gram-positive peptidoglycan 
is reported as an example of bacterial peptidoglycan. The cleavage sites 
of ligninases are not shown due to the complexity of the structure. In 
peptidoglycan, the green circle represents the dipeptide (D-Ala/L-Lys) 
connecting two peptide bridges (light green) from adjacent chains. Ara, 
L-Arabinose; CWDEs, cell wall degrading enzymes; GalA, D-Galacturonic 
Acid; Glc, D-Glucose; LPMO, lytic polysaccharide monooxygenase; NAG, 
N-acetylglucosamine; NAM, N-acetylmuramic acid; Xyl, D-Xylose. 
Giovannoni et al. (2020); reproduced with permission. 79
FIG. 8.1 Schematic structure of lignocelluloses (Baruah et al., 2018). 99
FIG. 8.2 Schematic of pretreatment effect on lignocellulosic biomass. Based on 
Mosier et al. (2005a,b). 100
FIG. 8.3 Overview of different pretreatment processes (Kumar and 
Sharma, 2017). 101
FIG. 9.1 Different feedstock currently used for ethanol production 
(Balan, 2013). 135
FIG. 9.2 Different feedstocks used in the first and second generation biorefinery 
for producing biofuels, biochemicals, food, and feed Balan (2013). 140
FIG. 10.1 Schematic representation of various steps involved in production of 
different value-added products from lignocellulosic biomass. 166
FIG. 10.2 Overall reaction mechanisms of lignocellulose to chemicals. F, 
fermentation; Hl, hydrolysis; dH, Dehydration; rH, rehydration; 
O, oxidation; H, hydrogenation; Hg, Hydrogenolysis; dP, 
Depolymerixation. Reproduced with permission (Putro et al., 2016). 172
FIG. 10.3 Depolymerization of cellulose to nanocellulose. Reproduced with 
permission (Lee et al., 2014). 174
FIG. 10.4 Roadmap of lignocellulosic biomass biorefinery to nanocellulose 
intermediate and chemicals. Reproduced with permission 
(Lee et al., 2014). 180
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FIG. 11.1 Structure of LB (Wang, Sun, and Sun, 2019). LB, lignocellulosic biomass. 188
FIG. 11.2 Schematic representation of acid-functionalized magnetic nanoparticles 
mediated pretreatment of lignocellulosic biomass. Reproduced with 
permission (Ingle et al., 2018). 190
FIG. 11.3 From crystalline to disrupted structure before and after pretreatment 
at different conditions. (A) Untreated corn stover, area pointed by the 
arrow is an intact cell wall; (B) nanoshear hybrid water pretreated CS; 
(C) 4 g/L NaOH NSHA pretreated CS, area pointed by the arrow is a 
discontinued structure with a reduced fiber length (fibrillation); 
(D) 20 g/L NaOH NSHA pretreated CS, area indicated by the circle is 
where cellulose crystalline structure breaks apart (another form of 
fibrillation); (E) 40 g/L NaOH NSHA pretreated CS, minipores and more 
disrupted fibers. Reproduced with permission (Wang et al., 2013). 
NSHA, Nano scale shear hybrid alkaline. 195
FIG. 11.4 Fibril aggregates on the surface of the cellulose crystalline structure; 
(A) 40g/l NaOH NSHA pretreated CS, nanofibril aggregates retained 
on the surface of a single cellulose fiber, diameters are around 
300–500 nm; (B) 40 g/L NaOH NSHA pretreated CS, more fibril 
aggregates with thinner diameters. Reproduced with permission 
(Wang et al., 2013). NSHA, Nano scale shear hybrid alkaline. 196
FIG. 11.5 Schematic illustration of the modified Taylore–Couette reactor 
(nanomixer). Reproduced with permission (Wang et al., 2013). 197
FIG. 12.1 A schematic illustration of the nanocomposite preparation process. 
(A) The ice-templating setup and (B) the vacuum infusion setup. 
Reproduced with permission (Nissila et al., 2019). 210
FIG. 12.2 Field emission scanning electron microscopy images for the 
fracture morphologies of (A) PHB/NCC-15, (B) PHB/acetylated NCC(II)-15, 
(C) PHB/acetylated NCC(IV)-15 nanocomposites. Reproduced 
with permission (Gan et al., 2017). 213
	List of figures