Organosolv lignin properties and their effects on enzymatic hydrolysis

Abstract

Lignin plays a crucial role in enzymatic hydrolysis of lignocellulosic biomass. To evaluate the correlation between lignin properties and its effects on enzymatic hydrolysis, five organosolv lignins (OLs) were isolated from woody biomass, and their physico-chemical properties and structural features were characterized. The effects of OL addition on enzymatic hydrolysis of microcrystalline cellulose (pure cellulose) were assessed first, which showed their disparate effects. The addition of three OLs increased the 72 h hydrolysis yield by 7.4% to 10.1%, while the addition of other two OLs reduced the 72 h hydrolysis yield by 3.2% to 20.4%. A strong correlation between the enzyme distribution coefficient on lignins and the 72 h hydrolysis yields indicated that the enzyme-lignin interaction played a significant role in determining the lignin effects. More importantly, a correlation between lignin properties (hydrophobicity, zeta potential, and particle size) and the enzyme distribution coefficient was established. Identifying the key lignin properties will give insights to reduce the lignin inhibition by altering the lignin properties, thereby promoting enzymatic hydrolysis of lignocellulose.

Sequential extraction of organosolv lignin from Chinese quince fruit: Structural features and antioxidant activities of the obtained fractions

“…The α-ethoxylated β-O-4' aryl ethers substructures (A'α) were founded by the correlations at δC/δH 81.0/4.60 ppm, implying the occurrence of α-ethoxylation during the pretreatment. Additionally, the methylene in α-ethoxylated β-O-4' aryl ethers substructures (A'α-CH2CH3) was founded at δC/δH 65.3/3.38 ppm, which confirmed that α-ethoxylation had occurred in β-O-4' linkages (Huang et al 2020). After fractionation, the α-ethoxylated β-O-4' aryl ether substructures still remained in F2 and F4, implying that the lignins with such substructures were dispersed into the fractions during sequential extraction.…”

“…The organosolv process has been demonstrated as an effective technique for the collection of sulfur-free, low molecular-weight lignin with few inorganic impurities (Hamauzu et al 2010;Huang et al 2020). In a previous study, the effect of extraction conditions on auto-catalyzed ethanol organosolv lignin (AEOL) from Chinese quince fruit was assessed, confirming the optimal conditions to collect AEOL with high antioxidant performance (Cheng et al 2020).…”