Yang Guangrong, An Xueying, Yang Shilong
College of Furniture and Industrial Design, Nanjing Forestry University, Nanjing, China.
School of Landscape Architecture, Jiangsu Vocational College of Agriculture and Forestry, Jurong, China.
Front Bioeng Biotechnol. 2021 Dec 14;9:807625. doi: 10.3389/fbioe.2021.807625. eCollection 2021.
Ball milling technology is the classical technology to isolate representative lignin in the cell wall of biomass for further investigation. In this work, different ball milling times were carried out on hardwood (poplar sawdust), softwood (larch sawdust), and gramineous material (bamboo residues) to understand the optimum condition to isolate the representative milled wood lignin (MWL) in these different biomass species. Results showed that prolonging ball milling time from 3 to 7 h obviously increased the isolation yields of MWL in bamboo residues (from 39.2% to 53.9%) and poplar sawdust (from 15.5% to 35.6%), while only a slight increase was found for the MWL yield of larch sawdust (from 23.4% to 25.8%). Importantly, the lignin substructure of -O-4 in the MWL samples from different biomasses can be a little degraded with the increasing ball milling time, resulting in the prepared MWL with lower molecular weight and higher content of hydroxyl groups. Based on the isolation yield and structure features, milling time with 3 and 7 h were sufficient to isolate the representative lignin (with yield over 30%) in the cell wall of bamboo residues and poplar sawdust, respectively, while more than 7 h should be carried out to isolate the representative lignin in larch sawdust.
球磨技术是从生物质细胞壁中分离代表性木质素以进行进一步研究的经典技术。在这项工作中，对硬木（杨木锯末）、软木（落叶松锯末）和禾本科材料（竹渣）进行了不同的球磨时间实验，以了解从这些不同生物质物种中分离代表性磨木木素（MWL）的最佳条件。结果表明，将球磨时间从3小时延长至7小时，明显提高了竹渣（从39.2%提高到53.9%）和杨木锯末（从15.5%提高到35.6%）中MWL的分离产率，而落叶松锯末的MWL产率仅略有增加（从23.4%提高到25.8%）。重要的是，随着球磨时间的增加，不同生物质的MWL样品中-O-4木质素亚结构会有一定程度的降解，导致制备的MWL分子量降低，羟基含量增加。基于分离产率和结构特征，3小时和7小时的球磨时间分别足以从竹渣和杨木锯末细胞壁中分离出代表性木质素（产率超过30%），而要从落叶松锯末中分离出代表性木质素则需要进行超过7小时的球磨。
