This study explored the mechanism that high degree of delignification (DD) inhibits enzymatic hydrolysis. Sample with DD of 86.22% achieved the highest cellulose conversion of 68.26%, and the cell wall exhibited defibrillation of macrofibrils and erosion of microfibrils during enzymatic hydrolysis. Cracks between microfibrils are formed within the cell wall, getting the largest specific surface area, which greatly enhanced cellulose conversion. However, high DD of 96.58% resulted in dramatic reduction of cellulose conversion to 56.60% which was evidenced to be the synergistic effect of internal cell wall collapse and microfibrils reaggregation. These ultrastructural changes dominated upon this condition and induced a more compact surface structure which significantly hinders the accessibility of cellulase. The CrI value increased after delignification but changed little with the increased DD, suggesting limited influence of DD on crystalline structure. The results indicate that certain amount of lignin retained may be essential to enhance cellulose conversion.

本研究探讨了高度去木质素（DD）抑制酶促水解的机理。DD为86.22％的样品实现了68.26％的最高纤维素转化率，并且细胞壁在酶促水解过程中表现出大纤维的除纤颤和微纤维的侵蚀。微纤维之间的裂缝形成在细胞壁内，从而获得最大的比表面积，从而大大提高了纤维素的转化率。然而，较高的DD为96.58％导致纤维素转化率显着降低至56.60％，这被证明是内部细胞壁塌陷和微纤维再聚集的协同作用。这些超微结构变化在这种情况下占主导地位，并诱导了更紧密的表面结构，从而显着阻碍了纤维素酶的可及性。CrI值在去木质素后增加，但随着DD的增加而变化不大，这表明DD对晶体结构的影响有限。结果表明，保留一定量的木质素对于提高纤维素转化率可能是必不可少的。