Understanding the effects of different residual lignin fractions in acid-pretreated bamboo residues on its enzymatic digestibility

Table 2 Physicochemical properties of solvent-extracted bamboo residues and extracted lignin fractions

Sample	Accessibility	Hydrophobicity	Crystallinity	B_hkl	D_hkl	Zeta potential	Molecular weight (kDa)
Sample	(mg/g)	(mg/mL)^a and (°)^b	(%)	(nm)	(nm)	(mV)	M_w	M_n
DAP-BR	218	0.7^a	38	3.03	0.403	−24.3 ± 0.5	–
Dio-BR	320	3.6^a	36	3.64	0.401	−20.4 ± 0.2	–
Eth-BR	236	3.1^a	39	3.45	0.402	−22.1 ± 1.1	–
THF-BR	251	3.0^a	34	3.99	0.400	−21.5 ± 0.3	–
DAP-MWL	–	76.4^b	–	–	–	−37.0 ± 0.3	9.1	2.9
Dio-MWL	–	76.2^b	–	–	–	−31.8 ± 0.2	10.8	3.6
Eth-MWL	–	73.8^b	–	–	–	−34.3 ± 0.3	13.0	4.6
THF-MWL	–	75.1^b	–	–	–	−37.0 ± 0.3	13.2	4.7
Dio-SL	–	69.5^b	–	–	–	−32.8 ± 0.2	2.4	0.7
Eth-SL	–	68.5^b	–	–	–	−29.1 ± 1.1	1.2	0.4
THF-SL	–	64.3^b	–	–	–	−26.1 ± 0.1	2.0	0.4
DAP-MWL	–	76.4^b	–	–	–	−37.0 ± 0.3	9.1	0.5

DAP-BR dilute acid-pretreated bamboo residues, Dio-BR DAP-BR extracted by 1,4-dioxane using a concentration of 96% (v/v, water/1,4-dioxane), Eth-BR DAP-BR extracted by ethanol extraction using a concentration of 95% (v/v, water/ethanol), THF-BR DAP-BR extracted by tetrahydrofuran using pure tetrahydrofuran; MWL milled wood lignin, SL surface lignin
^aAnalyzed by dye absorption
^bAnalyzed by water contact angle

ISSN: 2731-3654