Visualization of Miscanthus × giganteus cell wall deconstruction subjected to dilute acid pretreatment for enhanced enzymatic digestibility.
Visualization of Miscanthus × giganteus cell wall deconstruction subjected to dilute acid pretreatment for enhanced enzymatic digestibility.
复制标题
DOI：
10.1186/s13068-015-0282-3
复制
发表时间：
2015
影响因子：
6.3
通讯作者：
Xu F
中科院分区：
文献类型：
--
作者：
Ji Z;Zhang X;Ling Z;Zhou X;Ramaswamy S;Xu F
由于异质成分的复杂排列和分布而产生的木质纤维素植物细胞壁的自然顽抗阻碍了此类细胞壁的解构。稀酸预处理（DAP）是克服多糖酶促转化障碍的一种有吸引力的方法。在这项研究中，对一种生物能源作物模型芒草的节间进行 DAP 处理，产生了一系列细胞壁结构和化学成分发生改变的样品。全面研究了随之而来的形态和成分变化及其对糖化效率的可能影响。使用一系列显微和显微光谱技术，包括荧光显微镜（FM）、透射电子显微镜（TEM）和共焦拉曼显微镜（CRM）），可以获得相关的细胞壁结构和化学信息。 M. × giganteus 的 DAP 导致阿拉伯木聚糖溶解并以温度依赖性方式交联羟基肉桂酸。优化的预处理（1% H2SO4，170°C，30 分钟）使处理后的样品在 72 小时内糖化效率（51.20%）显着提高，糖得率比未处理样品（11.80%）提高了 4.4 倍。这种显着的改善可能与植物细胞壁由于预处理诱导的解构而发生的一系列变化有关，即相邻细胞壁之间基质的损失、半纤维素的选择性去除、酚类聚合物的重新分布和纤维素暴露的增加。还发现内细胞壁结构随之发生的变化，包括破坏、孔隙率增加和机械阻力损失，可以增强酶对纤维素的接触并进一步提高糖产量。 DAP 是一种通过破坏细胞壁的刚性和抵抗力来改善纤维素生物转化为葡萄糖的高效过程。这项工作中采用的最相关的微观和微分析技术的结合为评估解剖和成分变化对增强酶消化率的影响提供了至关重要的信息。本文的在线版本 (doi:10.1186/s13068-015-0282-3) 包含补充材料，可供授权用户使用。
The natural recalcitrance of lignocellulosic plant cell walls resulting from complex arrangement and distribution of heterogeneous components impedes deconstruction of such cell walls. Dilute acid pretreatment (DAP) is an attractive method to overcome the recalcitrant barriers for rendering enzymatic conversion of polysaccharides. In this study, the internodes of Miscanthus × giganteus, a model bioenergy crop, were subjected to DAP to yield a range of samples with altered cell wall structure and chemistry. The consequent morphological and compositional changes and their possible impact on saccharification efficiency were comprehensively investigated. The use of a series of microscopic and microspectroscopic techniques including fluorescence microscopy (FM), transmission electron microscopy (TEM) and confocal Raman microscopy (CRM)) enabled correlative cell wall structural and chemical information to be obtained. DAP of M. × giganteus resulted in solubilization of arabinoxylan and cross-linking hydroxycinnamic acids in a temperature-dependent manner. The optimized pretreatment (1% H2SO4, 170°C for 30 min) resulted in significant enhancement in the saccharification efficiency (51.20%) of treated samples in 72 h, which amounted to 4.4-fold increase in sugar yield over untreated samples (11.80%). The remarkable improvement could be correlated to a sequence of changes occurring in plant cell walls due to their pretreatment-induced deconstruction, namely, loss in the matrix between neighboring cell walls, selective removal of hemicelluloses, redistribution of phenolic polymers and increased exposure of cellulose. The consequently occurred changes in inner cell wall structure including damaging, increase of porosity and loss of mechanical resistance were also found to enhance enzyme access to cellulose and further sugar yield. DAP is a highly effective process for improving bioconversion of cellulose to glucose by breaking down the rigidity and resistance of cell walls. The combination of the most relevant microscopic and microanalytical techniques employed in this work provided information crucial for evaluating the influence of anatomical and compositional changes on enhanced enzymatic digestibility. The online version of this article (doi:10.1186/s13068-015-0282-3) contains supplementary material, which is available to authorized users.