Abstract:

Lignin, a renewable abundant natural aromatic compound, is recognized as the most prevalent aromatic polymer found in nature and serves as a promising sustainable feedstock for the production of high-value aromatic chemicals. Nevertheless, the inherent heterogeneity and intricate structure of lignin present considerable obstacles to its degradation and effective utilization. The presence of a diverse array of lignin-degrading enzymes in nature, each exhibiting a wide range of specificities, allows for enzyme-mediated biodegradation to overcome the limitations imposed by the recalcitrant structure of lignin, thereby enabling its degradation under mild conditions. Nonetheless, the expression, catalytic activity, and stability of natural lignin-degrading enzymes often fall short of expectations. Recent years have witnessed considerable progress in artificially regulating the synthesis and catalytic properties of lignin-degrading enzymes through heterologous expression and molecular modification. This paper begins with a succinct overview of the principal lignin-degrading enzymes and their catalytic characteristics. It subsequently emphasizes the advancements achieved in the heterologous overexpression of these enzymes and the enhancement of their catalytic efficiency, while thoroughly examining the existing theoretical and technological challenges and proposing targeted strategies to address these issues. Our aim is to provide a valuable reference for the development of more efficient lignin biodegradation systems and to contribute to the achievement of the "double carbon" objective.

Key words: lignin-degrading enzyme, artificial regulation, heterologous expression, enzyme engineering

摘要：

作为可再生生物质的重要组分，木质素是自然界储量最为丰富的芳香族高聚物，是芳香高值化学品合成的潜在绿色原料。然而，木质素的异质性和复杂结构给其降解利用造成了严峻挑战。自然界存在种类繁多、特异性多样的木质素降解酶，使得酶介导的生物降解能够突破木质素顽固性结构的限制，在温和条件下降解木质素。尽管如此，天然木质素降解酶的表达量、催化活性和稳定性等往往不尽人意。近年来，通过蛋白质表达调控、酶分子改造，木质素降解酶的合成和催化性能的人工调控已取得诸多优秀成果。鉴于此，本文首先对重要的木质素降解酶及其催化特性进行了简要介绍；在此基础上，重点总结了木质素降解酶的表达和催化性能强化方面的研究进展，对当前面临的理论和技术挑战进行了深入分析并提出了针对性的应对策略。希望为更高效木质素生物降解体系的开发提供有价值的参考，助力“双碳”目标的实现。

关键词: 木质素降解酶, 人工调控, 异源表达, 酶工程