The thermal degradation reactivities of cellulose and hemicellulose are substantially different in Japanese cedar (Cryptomeria japonica, a softwood) and Japanese beech (Fagus crenata, a hardwood). Uronic acid and its salts act as acid and base catalysts, respectively, and their specific placement in the cell walls has been considered a factor that influences degradation reactivity. In this study, the role of lignin in degradation reactivity was investigated using holocellulose prepared from cedar and beech woods. The thermal degradation reactivities of cellulose and hemicellulose in holocellulose were evaluated according to the recovery of hydrolyzable sugars from heat-treated samples and compared with those of wood samples. Results show that the reactivities of xylan and glucomannan in both woods became similar to those of the corresponding isolated samples when lignin was removed. By contrast, the cellulose in both woods became more reactive when lignin was removed, and the degradation could be separated into two modes depending on the reactivity. These results were analyzed in terms of the effect of lignin on the matrix of cell walls and the interaction between the matrix and surface molecules of cellulose microfibrils. Differential thermogravimetric curves of the holocellulose samples were obtained and explained in terms of the degradation of hemicellulose and cellulose. The reported findings will provide insights into the research fields of wood pyrolysis and cell wall ultrastructures.

中文翻译：

---

脱木素处理对木质细胞壁中半纤维素和纤维素热降解反应活性的影响

在日本雪松（Cryptomeria japonica，一种软木）和日本山毛榉（Fagus crenata，一种硬木）中，纤维素和半纤维素的热降解反应性有很大不同。糖醛酸及其盐分别充当酸和碱的催化剂，并且它们在细胞壁中的特定位置被认为是影响降解反应性的因素。在这项研究中，使用从雪松和山毛榉木中制备的全纤维素对木质素在降解反应性中的作用进行了研究。根据从热处理样品中回收的可水解糖的回收率，评估纤维素和半纤维素在全纤维素中的热降解反应性，并将其与木材样品进行比较。结果表明，当去除木质素后，两种木材中的木聚糖和葡甘露聚糖的反应性变得与相应的分离样品相似。相反，当去除木质素时，两种木材中的纤维素都变得更具反应性，并且降解可以根据反应性分为两种模式。从木质素对细胞壁基质的作用以及基质与纤维素微纤维表面分子之间的相互作用方面分析了这些结果。获得了全纤维素样品的热重差曲线，并根据半纤维素和纤维素的降解进行了解释。报道的发现将提供对木材热解和细胞壁超微结构研究领域的见识。去除木质素后，两种木材中的纤维素都变得更具反应性，根据反应性，降解可分为两种模式。从木质素对细胞壁基质的作用以及基质与纤维素微纤维表面分子之间的相互作用方面分析了这些结果。获得了全纤维素样品的热重差曲线，并根据半纤维素和纤维素的降解进行了解释。报道的发现将提供对木材热解和细胞壁超微结构研究领域的见识。去除木质素后，两种木材中的纤维素都变得更具反应性，根据反应性，降解可分为两种模式。从木质素对细胞壁基质的作用以及基质与纤维素微纤维表面分子之间的相互作用方面分析了这些结果。获得了全纤维素样品的热重差曲线，并根据半纤维素和纤维素的降解进行了解释。报道的发现将提供对木材热解和细胞壁超微结构研究领域的见识。从木质素对细胞壁基质的作用以及基质与纤维素微纤维表面分子之间的相互作用方面分析了这些结果。获得了全纤维素样品的热重差曲线，并根据半纤维素和纤维素的降解进行了解释。报道的发现将提供对木材热解和细胞壁超微结构研究领域的见识。从木质素对细胞壁基质的作用以及基质与纤维素微纤维表面分子之间的相互作用方面分析了这些结果。获得了全纤维素样品的热重差曲线，并根据半纤维素和纤维素的降解进行了解释。报道的发现将提供对木材热解和细胞壁超微结构研究领域的见识。