Insight into fermentable sugar recovery process from sugarcane bagasse: in silico elucidation of enzymatic hydrolysis and techno-economic assessment

Figures & data

Figure 1. Overall steps considered for the study.

Figure 2. Structural morphology of sugarcane bagasse: (a) before hydrolysis, (b) after pretreatment and (c) after hydrolysis.

Figure 3. FTIR spectra of sugarcane bagasse: (a) before hydrolysis and (b) after hydrolysis.

Figure 4. (a) TGA curve (b) DTA curve of sugarcane bagasse [BP – before pretreatment; AP – after pretreatment; AH – after hydrolysis].

Table 1. Elemental analysis of sugarcane bagasse.

	Element content
Bagasse	Carbon (%)	Hydrogen %	Nitrogen %	Sulfur (%)
Untreated	37.93	5.265	0	0.301
Pretreated	38.58	5.725	0	0.307
Hydrolysed	39.86	5.772	0	0.309

Figure 5. Flow sheet for sugar recovery from sugarcane bagasse using SuperPro Designer.

Figure 6. Cost analysis of the process obtained using SuperPro Design: (a) overall cost and (b) item cost.

Figure 7. Cartoon representation of PBD structure: (i) Generated model viewed in Chimera (a) Endoglucanase and (b) β-glucosidase, (ii) Ligands (a) Cellulose and (b) Glucose [Yellow: Hydrogen, Blue: Oxygen, Red: Carbon], (iii) Endoglucanase (a) Chain A of 3QX3 structure for cluster 1 after docking of a molecule with the ligand using Swiss Dock and (b) The magnified image of the interaction of molecule with ligand; (iv) Beta-glucosidase (a) Chain A of 3WBE structure for cluster 5 after docking of a molecule with the ligand using Swiss Dock and (b) The magnified image of the interaction of molecule with ligand [Red colour: Coil, Yellow colour: Helix, Blue colour: Strand, Cyan colour: Ligand] obtained by Swiss Dock after docking.

Table 2. Summary of successfully produced models for endoglucanase and β-glucosidase.

Enzymes	Endoglucanase		β-glucosidase
Models	Mod pdf	DOPE score	Mod pdf	DOPE score
1	1893.76514	−43341.4883	2538.93726	−61136.5
2	2053.36865	−42977.0664	2579.1665	−61129.4
3	2013.15796	−42986.7617	2439.96289	−61277.9
4	2133.64111	−43209.9961	2481.34863	−61267.4
5	1954.23572	−43135.668	2470.73413	−61291.5
6	2019.04138	−43049.668	2850.24365	−60397.3
7	1995.66077	−43132.3281	2531.15381	−61125.6
8	2124.07568	−43194.7969	2751.71484	−60877.3
9	1954.49243	−43148.1797	2587.41699	−60532.6
10	2176.72681	−42913.5859	2599.6582	−60673.2

Table 3. Plot statistics of the generated models using PROCHECK [A: Endoglucanase III and B: β-glucosidase].

					Comparison values
	No. of data points		Parameter value		Typical value		Band width		No. of band width from mean
Stereo-chemical parameter	A	B	A	B	A	B	A	B	A	B
% Residues in A, B, L	350	430	91.4	91.9	88.2	88.2	10.0	10.0	0.3	0.4
Omega angle SD	416	486	3.8	4.0	6.0	6.0	3.0	3.0	−0.7	−0.7
Bad contacts/100 residues	4	3	1.0	0.6	1.0	1.0	10.0	10.0	0.0	0.0
Zeta angle SD	372	449	1.2	1.3	3.1	3.1	1.6	1.6	−1.2	−1.2
H-bond energy SD	228	319	0.8	0.7	0.7	0.7	0.2	0.2	0.5	0.2
Overall G-factor	418	489	0	0	−0.2	−0.2	0.3	0.3	0.5	0.6

Table 4. Poses obtained through molecular modelling using Swiss Dock.

	Poses
Proteins	Cluster	H bonds	Energy (Kcal/mol)	ΔG (Kcal/mol)
Endoglucanase	1	2	41.599	−6.624
	2	1	26.082	−7.260
	3	1	30.834	−6.960
	4	1	32.131	−7.008
	5	1	47.391	−6.644
	6	1	36.480	−6.75
Beta-glucosidase	1	1	8.463	−5.86
	2	2	6.995	−6.25
	3	2	9.735	−6.16
	4	2	3.306	−7.02
	5	2	12.663	−5.52
	6	2	6.534	−6.53