Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry, Jiangsu Province Key Laboratory of Biomass Energy and Materials, Nanjing 210042.
Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China.
Bioresour Technol. 2022 Sep;359:127462. doi: 10.1016/j.biortech.2022.127462. Epub 2022 Jun 11.
A delignification saturation point (DSP) was observed for bamboo alkaline hydrogen peroxide pretreatment (AHP). Lignin removal was increased from 52.23% to ∼70% when increasing HO dosage from 0% to 2% at the optimum pH, but it cannot be further reinforced as increasing the HO. With partial lignin preserved, the glucan hydrolysis yield was found to have a ceiling of ∼80%. This study indicated a strong association between enzymatic digestibility and lignin removal. Anatomical analysis by fluorescence microscope and confocal Raman microscope revealed that the undegradable lignin was mainly existing in the cell corner of sclerenchyma fibers, causing the DSP in the bamboo AHP. Finally, the residual lignin in pretreated bamboo was characterized with GPC, HSQC NMR, and P NMR, which revealed the nature of DSP. This study could help to understand the lignin modification during the AHP and further contribute to the establishment of a chemical-saving biorefinery.
竹材碱性过氧化氢预处理存在脱木质素饱和点（DSP）。在最佳 pH 值下，当 HO 用量从 0%增加到 2%时，木质素去除率从 52.23%增加到约 70%，但进一步增加 HO 并不能进一步增强。当保留部分木质素时，发现葡聚糖水解率达到约 80%的上限。这项研究表明酶解可消化性与木质素去除之间存在很强的关联。荧光显微镜和共聚焦拉曼显微镜的解剖分析表明，不可降解的木质素主要存在于厚壁纤维的细胞角中，导致竹材碱性过氧化氢预处理中的 DSP。最后，用 GPC、HSQC NMR 和 P NMR 对预处理竹材中的残余木质素进行了表征，揭示了 DSP 的本质。这项研究有助于理解 AHP 过程中的木质素修饰，并进一步为建立节省化学品的生物炼制工艺做出贡献。
