Fermentable sugars have long been a research focus and are an important product of biorefining. Many researches have been dedicated to improving the yield of fermentable sugars from lignocellulose. However, an understanding of the residual lignin in pretreated and hydrolyzed residues remains lacking. In this work, wheat straw (WS) was autohydrolyzed under increasingly severe reaction conditions (temperature of 160–200 °C and reaction times of 20–60 min), and the anatomical characteristics of the resultant biomass were carefully analyzed to provide visual evidences of the fate of lignin. The results showed that 12.3 g/L of total xylose can be produced from autohydrolysis of WS. Further, the enzymatic hydrolysis efficiency of WS increased by 70.3% after autohydrolysis at 200 °C for 60 min. Under those conditions, the cell wall of WS were found to be significantly damaged, and the vascular bundles of lignin in the cell wall was firstly removed depending on the distribution of constituent compounds in the cell wall. The NMR analysis showed that the β-O-4 link bond and G-lignin units were affected the most during the autohydrolysis of WS, providing a route to understand the changes in WS lignin before and after autohydrolysis. It is our hope that these findings will lead to more targeted approaches for WS pretreatment and increase its applicability to biorefinery processes.

可发酵糖长期以来一直是研究重点，是生物精炼的重要产品。许多研究致力于提高木质纤维素中可发酵糖的产量。然而，仍然缺乏对预处理和水解残留物中残留木质素的了解。在这项工作中，小麦秸秆 (WS) 在越来越严酷的反应条件下（温度为 160-200 °C，反应时间为 20-60 分钟）自水解，并仔细分析了所得生物质的解剖学特征，以提供视觉证据木质素的命运。结果表明，WS自水解可产生12.3 g/L的总木糖。此外，在 200°C 下自水解 60 分钟后，WS 的酶水解效率提高了 70.3%。在这些条件下，发现 WS 的细胞壁受到显着破坏，根据组成化合物在细胞壁中的分布，首先去除细胞壁中的木质素维管束。核磁共振分析表明，β -O-4连接键和G-木质素单元在WS自水解过程中受到的影响最大，为了解WS自水解前后木质素的变化提供了途径。我们希望这些发现能够为 WS 预处理提供更有针对性的方法，并提高其在生物精炼过程中的适用性。