State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, People's Republic of China.
J Agric Food Chem. 2011 Aug 24;59(16):8691-701. doi: 10.1021/jf201508g. Epub 2011 Jul 20.
Lignocellulose materials are potentially valuable resources for transformation into biofuels and bioproducts. However, their complicated structures make it difficult to fractionate them into cellulose, hemicelluloses, and lignin, which limits their utilization and economical conversion into value-added products. This study proposes a novel and feasible fractionation method based on complete dissolution of bagasse in 1-butyl-3-methylimidazolium chloride ([C(4)mim]Cl) followed by precipitation in acetone/water (9:1, v/v) and extraction with 3% NaOH solution. The ionic liquid [C(4)mim]Cl was easily recycled after concentration and treatment with acetonitrile. (1)H NMR analysis confirmed that there was no obvious difference between the recycled [C(4)mim]Cl and fresh material. Bagasse was fractionated with this method to 36.78% cellulose, 26.04% hemicelluloses, and 10.51% lignin, accounting for 47.17 and 33.85% of the original polysaccharides and 54.62% of the original lignin, respectively. The physicochemical properties of the isolated fractions were characterized by chemical analysis, high-performance anion exchange chromatography (HPAEC), gel permeation chromatography (GPC), Fourier transform infrared (FT-IR), and (1)H and 2D (13)C-(1)H correlation (HSQC) nuclear magnetic resonance spectroscopy. The results showed that the acetone-soluble lignin and alkaline lignin fractions had structures similar to those of milled wood lignin (MWL). The easy extraction of the noncellulose components from homogeneous bagasse solution and amorphous regenerated materials resulted in the relatively high purity of cellulosic fraction (>92%). The hemicellulosic fraction was mainly 4-O-methyl-D-glucuronoxylans with some α-L-arabinofuranosyl units substituted at C-2 and C-3.
木质纤维素材料是将其转化为生物燃料和生物制品的有价值资源。然而，其复杂的结构使得将它们分离为纤维素、半纤维素和木质素变得困难，从而限制了它们的利用和经济转化为增值产品。本研究提出了一种基于在 1-丁基-3-甲基咪唑氯 ([C(4)mim]Cl) 中完全溶解蔗渣，然后在丙酮/水 (9:1，v/v) 中沉淀和 3% NaOH 溶液中萃取的新型可行的分离方法。离子液体 [C(4)mim]Cl 在浓缩和用乙腈处理后很容易回收。(1)H NMR 分析证实，回收的 [C(4)mim]Cl 与新鲜材料没有明显区别。用该方法将蔗渣分离为 36.78%的纤维素、26.04%的半纤维素和 10.51%的木质素，分别占原始多糖的 47.17%和 33.85%和原始木质素的 54.62%。通过化学分析、高效阴离子交换色谱 (HPAEC)、凝胶渗透色谱 (GPC)、傅里叶变换红外 (FT-IR) 和 (1)H 和二维 (13)C-(1)H 相关 (HSQC) 核磁共振波谱对分离的组分进行了表征。结果表明，丙酮可溶木质素和碱性木质素组分的结构与磨木木质素 (MWL) 相似。从均相蔗渣溶液和无定形再生材料中容易提取非纤维素成分导致纤维素组分的相对较高纯度 (>92%)。半纤维素组分主要为 4-O-甲基-D-葡萄糖醛酸木聚糖，带有一些在 C-2 和 C-3 取代的α-L-阿拉伯呋喃糖基单元。
