生物炼制过程中木质素高值转化研究进展

Advances in lignin valorization from a biorefinery concept

摘要:

木质素高值转化对于提升生物炼制经济性，促进社会经济绿色发展具有重要意义。然而，木质素结构复杂且不均一，其高值化利用仍存在技术壁垒，使得木质素应用尚未形成规模。文中首先综述了当前生物炼制过程中木质素高值转化面临的主要挑战。然后通过比较不同预处理技术对木质素分离、性质及其利用的主要影响，详细阐述了基于生物炼制理念发展的新型组合预处理技术。其次，针对木质素本征结构特性导致其利用效率低等问题，进一步详述了溶剂分级、膜分级、梯度沉淀分级等分级利用策略对克服木质素不均一性，改善其可加工性能的重要影响。再次，针对木质素利用策略，系统比较了木质素热化学转化和生物转化，结合生物质预处理及木质素分级，阐述了以生物炼制理念进行木质素高值转化的新策略。最后，总结了木质素利用过程中存在的挑战性问题，展望了木质素高效分离、分级及转化过程发展的新策略和新趋势。

关键词:木质素，生物炼制，分级，热化学转化，生物转化，过程工程

Abstract:

Lignin valorization for fuels and value-added products is essential to enhance the profitability and sustainability of biorefineries. Due to the complex and heterogeneous structure of lignin, technical barriers hinder the implementation of economic lignin utilization. Here, we summarize the major challenges facing lignin valorization processes. Different pretreatment methods, especially emerging combinatorial pretreatment approaches for isolating and tailoring lignin are introduced. To overcome the heterogeneity of lignin structure and improve lignin processability, advances in fractionation approaches including organosolv extraction, membrane technology, and gradient precipitation are analyzed and presented. Furthermore, progress in lignin valorization by thermochemical and biological conversion coupling with pretreatment and fractionation are systematically reviewed. Finally, we discuss advanced strategies and perspectives for future research involving biomass pretreatment, lignin fractionation and conversion processes.

Key words:lignin, biorefineries, fractionation, thermochemical conversion, bioconversion, process engineering