Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, China.
Forestry and Landscape Architecture, Anhui Agricultural University, Hefei 230036, China.
Int J Biol Macromol. 2023 Jun 30;241:124461. doi: 10.1016/j.ijbiomac.2023.124461. Epub 2023 Apr 21.
Bamboo (Phyllostachys pubescens) is an attractive biomass block to develop biorefining industry, however, less emphasis has been placed on elucidating the chemical linkage variations of lignin and LCC between different bamboo cell walls. Here, purified milled wood lignin (MWLp) and lignin-carbohydrate complex (LCC) were isolated from bamboo (Phyllostachys pubescens) fibers (BF) and parenchyma cells (PC), respectively. The variations of structure features and chemical linkages of lignin and LCC were investigated via FT-IR, 2D HSQC NMR, and P NMR techniques. 2D HSQC NMR revealed that β-O-4 alkyl-aryl ether linkages and resinol (β-β) substructure were the main substructures in BF-MWLp and PC-MWLp. β-1 linkages existed in the PC-MWLp (3.18/100 Ar), but not in BF-MWLp. Moreover, tricin, as a flavonoid compound, was only detected in the BF-MWLp. The amount of the syringyl (S) units of PC-MWLp was higher than BF-MWLp. The results indicated that phenyl glycoside (PhGlc) bonds (mainly lignin and xylan) were the predominant chemical linkage type of LCC bonds in BF-LCC and PC-LCC, and the high contents of PhGlc bonds (45.53/100 Ar) were presented in PC. Our finding can provide a reference for the structural variations of lignin and LCC between the different bamboo cell walls.
竹子（Phyllostachys pubescens）是一种很有吸引力的生物量块状物，可用于发展生物炼制产业，但对于阐明不同竹壁细胞壁之间木质素和 LCC 的化学连接变化，人们的重视程度较低。在这里，分别从竹纤维（BF）和薄壁细胞（PC）中分离出了纯化的磨木木素（MWLp）和木质素-碳水化合物复合体（LCC）。通过 FT-IR、2D HSQC NMR 和 P NMR 技术研究了木质素和 LCC 的结构特征和化学连接的变化。2D HSQC NMR 表明，BF-MWLp 和 PC-MWLp 中的主要亚结构是β-O-4 烷基-芳基醚键和愈创木基（β-β）亚结构。β-1 键存在于 PC-MWLp（3.18/100 Ar）中，但不存在于 BF-MWLp 中。此外，作为一种类黄酮化合物的松柏醇，仅在 BF-MWLp 中被检测到。PC-MWLp 的愈创木基（S）单元的量高于 BF-MWLp。结果表明，BF-LCC 和 PC-LCC 中 LCC 键的主要化学连接类型是苯甲酰基葡萄糖苷（PhGlc）键（主要是木质素和木聚糖），且 PC 中 PhGlc 键的含量较高（45.53/100 Ar）。我们的发现可为不同竹壁细胞壁之间木质素和 LCC 的结构变化提供参考。
