Enhancement of the antioxidant abilities of lignin and lignin-carbohydrate complex from wheat straw by moderate depolymerization via LiCl/DMSO solvent catalysis.

A facile and environmentally-friendly strategy for increasing antioxidant activity is a crucial issue for value-added lignin and lignin-carbohydrate complex (LCC) as alternative antioxidants. However, the antioxidant activities of lignin and LCC by the traditional solid-liquid extraction (SLE) methods were restricted by the relatively lower solubility induced from high molecular weight (Mw), and the less functional groups including, phenolic hydroxyl and carboxyl. To improve the antioxidantion of lignin and LCC, lithium chloride/dimethyl sulfoxide (LiCl/DMSO) solvent fractionation (LDSF) was conducted to increase the functional groups and reduce Mw, in which LiCl/DMSO acted triple roles as solvent, acid, and metal chloride catalyst for the depolymerization reaction synchronously.

Efficient isolation of organosolv lignin-carbohydrate complexes (LCC) with high antioxidative activity via introducing LiCl/DMSO dissolving.

Lignin-carbohydrate complexes (LCC) have shown great potential as biocompatible antioxidants. But it is difficult to isolate LCC efficiently from lignocellulose by traditional Solid-Liquid Extraction method (SLE), which is blamed to the innate bioimpedance caused by the complex supramolecular structure of the lignocellulose, and a great mass transferring resistance between the extracting solution and solid lignocellulose. To release these restrictions above and improve the efficiency of LCC isolation, a modified isolating method named Liquid-Liquid Extraction (LLE) was proposed, in which ball-milled wheat stalk was dissolved in lithium chloride/dimethyl sulfoxide (LiCl/DMSO) solution, then regenerated by dioxane aqueous to extract LL-LCCs.