木质素是自然界中最丰富的可再生芳香族聚合物,其高附加值化利用可减少目前木质素资源燃烧所导致的资源浪费和环境污染。生物质细胞壁中三大组分(纤维素、半纤维素和木质素)通过共价键和氢键形成了致密而复杂的细胞壁结构,使得木质素难以高效分离。若要实现生物质木质素高效分离,首先需明确原料中木质素的分子结构特点和活性基团。基于木质素结构明确的生物质原料才能够更有效地选择和开发木质素解离及解聚方法。笔者主要概述了目前结构分析用的木质素分离和结构分析方法研究进展,重点阐述了液体核磁共振技术在分离木质素定性和定量结构方面的应用,并基于目前的研究进展提出了该领域的研究趋势。总之,木质素的结构解析将为树木基因调控、林木遗传育种和木质纤维原料的生物炼制提供相关理论依据。
Lignin is the most abundant renewable aromatic polymer in nature. Finding value-added applications of the lignin can reduce the waste of resources and environmental pollution caused by the burning of the lignin such as it does in pulp and paper making process. The three main components (cellulose, hemicelluloses, and lignin) in the plant cell wall constitute a complex cell wall structure through forming covalent bonds and hydrogen bonds, which leads to the fact that the lignin is difficult to be separated efficiently from plant cell wall. To achieve the efficient isolation of the lignin from biomass, it is necessary to clarify the molecular structure and functional groups of the lignin in differ- ent lignocellulosic raw materials. Based on the identified structures of the lignin macromolecules, efficient isolation methods can be better selected and developed. This paper reviewed the recent advances in the lignin isolation methods for the structural analysis purpose and the latest advances in the structural analysis of the lignin. The application of liq- uid-state nuclear magnetic resonance (NMR) techniques in the qualitative and quantitative structural analysis of the lignin was reviewed in detail. In addition, based on the current research progress, trends of future research in this field were proposed. In short, the structural analysis of the lignin will provide theoretical basis for the gene regulation and genetic breeding of tree as well as biorefinery of lignocellulosic biomass.