Unveiling the Structural\nCharacteristics of Lignin\nand Lignin–Carbohydrate Complexes in Fibers and Parenchyma\nCells of Moso Bamboo during Different Growing Years

Understanding and recognizing the structural characteristics\nof\nlignin–carbohydrate complexes (LCCs) and lignin in different\ngrowth stages and tissue types of bamboo will facilitate industrial\nprocesses and practical applications of bamboo biomass. Herein, the\nLCC and lignin samples were sequentially isolated from fibers and\nparenchyma cells of bamboo with different growth ages. The diverse\nyields of sequential fractions not only reflect the different biomass\nrecalcitrance between bamboo fibers and parenchyma cells but also\nuncover the structural heterogeneity of these tissues at different\ngrowth stages. The molecular structures and structural inhomogeneities\nof the isolated lignin and LCC samples were comprehensively investigated.\nThe results showed that the structural features of lignin and LCC\nlinkages in parenchyma cells were abundant in β-<i>O</i>-4 linkages but less with carbon–carbon linkages, suggesting\nthat lignin and cross-linked LCC in parenchyma cells are simple in\nnature and easily to be tamed and tractable in the current biorefinery.\nParallelly, the different ball-milled samples were directly characterized\nby high-resolution (800 M) solution-state 2D-HSQC NMR to analyze the\nwhole lignocellulosic material. Overall, the scheme presented in this\nstudy will provide a comprehensive understanding of lignin and LCC\nlinkages in fibers and parenchyma cells of bamboo and enable the utilization\nof bamboo biomass.