Formation and Identification of Lignin–Carbohydrate Complexes in Pre-hydrolysis Liquors

Abstract

The lignin−carbohydrate complexes (LCCs) typically present in the liquors produced in the pre-hydrolysis of biomass cause severe difficulties in downstream fractionation. To address this issue, a series of LCC samples were accessed from solutions obtained from the pre-hydrolysis of extractive-free pine wood meal (H-LCC) and compared with LCC obtained from the corresponding residues (B-LCC). Chromatographic and spectroscopic techniques revealed that 8.2% of the lignins were degraded at 160 °C, resulting from the breakage of β-O-4′ linkages during pre-hydrolysis. Meanwhile, (reactive) hemicelluloses were mainly removed from the fibers' cell walls. Some hemicelluloses in the prehydrolysis liquor, such as glucomannans, were associated with degraded lignin fragments via ether and ester bonds. However, the newly formed LCCs were pH-labile and underwent rapid hydrolysis. Overall, we reveal details about LCC formation and degradation during pre-hydrolysis at given temperatures, critically important in efforts to improve biomass processing and valorization.

Protective mechanism of fruit vinegar polyphenols against AGEs-induced Caco-2 cell damage

“…Mango vinegar had the highest scavenging rate of ABTS free radicals up to 83.28 ± 0.76%. It was probably because the polyphenols in fruit vinegar had hydroxyl groups, which can combine with unstable molecules to generate stable substances and finally achieved anti-oxidation effect ( Brglez Mojzer, Knez Hrnčič, Škerget, Knez, & Bren, 2016 , Feng et al, 2023 ). In terms of comprehensive antioxidant indicators, the scavenging ability of different free radicals was different, which may be caused by the different types and contents of polyphenols in different fruit vinegars ( Olszowy, 2019 ).…”

Composition of Lignocellulose Hydrolysate in Different Biorefinery Strategies: Nutrients and Inhibitors

“…After alkaline pretreatment, the lignin-rich black liquor generally requires solid-liquid separation before subsequent saccharification and utilization [86]. Inhibitors in the sugar solution, besides unwashed components of black liquor, mainly include lignin fragments deposited on celluloses and LCC (lignin-carbohydrate complexes) released from the fragmented cellulose [87,88]. The effective utilization of the separated lignin is the key to the economic viability of the entire biorefinery process.…”

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“…Additionally, lotus procyanidins improved the water holding capacity of rice starch, hindering the recrystallization. Lotus procyanidins also formed a weak gel structure with rice starch, inhibiting the early retrogradation of starch to some extent. , …”

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