Comparative study of acid- and alkali-catalyzed 1,4-butanediol pretreatment for co-production of fermentable sugars and value-added lignin compounds

Table 4 Physiochemical properties of recovered lignin from acid- or alkali-catalyzed BDO pretreatment

	Lignin yield (%)	Mw (g/mol)	Mn (g/mol)	PDI (Mw/Mn)	ATR-FTIR spectra			Antioxidant Capacity (RSI)
Pretreatment	Lignin yield (%)	Mw (g/mol)	Mn (g/mol)	PDI (Mw/Mn)	S + G condensed (1329 cm⁻¹)	Phenolic OH (1367 cm⁻¹)	OH (3338 cm⁻¹)	Antioxidant Capacity (RSI)
HCl-BDO 10 mM	9.39	3308	1835	1.80	0.87	0.46	0.49	0.49
HCl-BDO 20 mM	27.10	4038	1992	2.03	0.89	0.55	0.83	0.56
HCl-BDO 30 mM	49.34	4557	2113	2.16	0.90	0.57	0.85	0.60
HCl-BDO 40 mM	66.89	4032	1943	2.08	0.89	0.60	0.86	0.69
HCl-BDO 50 mM	69.66	3056	1698	1.80	0.87	0.60	0.88	0.76
NaOH-BDO 250 mM	34.82	3338	1130	2.95	0.83	0.45	0.50	0.57
NaOH-BDO 300 mM	44.90	3432	1209	2.84	0.88	0.46	0.51	0.57
NaOH-BDO 350 mM	49.21	2692	985	2.73	0.86	0.50	0.67	0.59
NaOH-BDO 400 mM	53.84	2434	1001	2.43	0.80	0.49	0.66	0.60
NaOH-BDO 450 mM	57.22	2039	933	2.19	0.80	0.48	0.55	0.62

ISSN: 2731-3654