Foster Cliff E, Martin Tina M, Pauly Markus
Great Lakes Bioenergy Research Center, Michigan State University, USA.
J Vis Exp. 2010 Mar 12(37):1837. doi: 10.3791/1837.
The need for renewable, carbon neutral, and sustainable raw materials for industry and society has become one of the most pressing issues for the 21st century. This has rekindled interest in the use of plant products as industrial raw materials for the production of liquid fuels for transportation(2) and other products such as biocomposite materials(6). Plant biomass remains one of the greatest untapped reserves on the planet(4). It is mostly comprised of cell walls that are composed of energy rich polymers including cellulose, various hemicelluloses, and the polyphenol lignin(5) and thus sometimes termed lignocellulosics. However, plant cell walls have evolved to be recalcitrant to degradation as walls contribute extensively to the strength and structural integrity of the entire plant. Despite its necessary rigidity, the cell wall is a highly dynamic entity that is metabolically active and plays crucial roles in numerous cell activities such as plant growth and differentiation(5). Due to the various functions of walls, there is an immense structural diversity within the walls of different plant species and cell types within a single plant(4). Hence, depending of what crop species, crop variety, or plant tissue is used for a biorefinery, the processing steps for depolymerisation by chemical/enzymatic processes and subsequent fermentation of the various sugars to liquid biofuels need to be adjusted and optimized. This fact underpins the need for a thorough characterization of plant biomass feedstocks. Here we describe a comprehensive analytical methodology that enables the determination of the composition of lignocellulosics and is amenable to a medium to high-throughput analysis (Figure 1). The method starts of with preparing destarched cell wall material. The resulting lignocellulosics are then split up to determine its monosaccharide composition of the hemicelluloses and other matrix polysaccharides1, and its content of crystalline cellulose(7). The protocol for analyzing the lignin components in lignocellulosic biomass is discussed in Part I(3).
工业和社会对可再生、碳中和及可持续原材料的需求已成为21世纪最紧迫的问题之一。这重新燃起了人们对将植物产品用作工业原料以生产运输用液体燃料（2）以及生物复合材料等其他产品（6）的兴趣。植物生物质仍然是地球上最大的未开发储备之一（4）。它主要由细胞壁组成，细胞壁由富含能量的聚合物构成，包括纤维素、各种半纤维素和多酚类木质素（5），因此有时被称为木质纤维素。然而，植物细胞壁已进化得难以降解，因为细胞壁对整个植物的强度和结构完整性有很大贡献。尽管细胞壁具有必要的刚性，但它是一个高度动态的实体，具有代谢活性，并在植物生长和分化等众多细胞活动中发挥关键作用（5）。由于细胞壁具有多种功能，不同植物物种以及同一植物内不同细胞类型的细胞壁在结构上存在巨大差异（4）。因此，根据用于生物炼制的作物种类、作物品种或植物组织的不同，通过化学/酶促过程进行解聚以及随后将各种糖类发酵为液体生物燃料的加工步骤需要进行调整和优化。这一事实凸显了对植物生物质原料进行全面表征的必要性。在此，我们描述了一种全面的分析方法，该方法能够测定木质纤维素的组成，并且适用于中高通量分析（图1）。该方法首先制备脱淀粉细胞壁材料。然后将得到的木质纤维素进行分离，以确定其半纤维素和其他基质多糖的单糖组成（1）以及结晶纤维素的含量（7）。分析木质纤维素生物质中木质素成分的实验方案将在第一部分进行讨论（3）。
