Gao Le, Jiang Fangting, Zhang Zhaokun, Bao Tongtong, Zhu Daochen, Wu Xin
Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
International Joint Laboratory on Synthetic Biology and Biomass Biorefinery, Biofuels Institute, School of Emergency Management, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, China.
Sci China Life Sci. 2025 Apr;68(4):994-1009. doi: 10.1007/s11427-024-2792-x. Epub 2024 Dec 18.
Lignin, an energy-rich and adaptable polymer comprising phenylpropanoid monomers utilized by plants for structural reinforcement, water conveyance, and defense mechanisms, ranks as the planet's second most prevalent biopolymer, after cellulose. Despite its prevalence, lignin is frequently underused in the process of converting biomass into fuels and chemicals. Instead, it is commonly incinerated for industrial heat due to its intricate composition and resistance to decomposition, presenting obstacles for targeted valorization. In contrast to chemical catalysts, biological enzymes show promise not only in selectively converting lignin components but also in seamlessly integrating into cellular structures, offering biocatalysis as a potentially efficient pathway for lignin enhancement. This review comprehensively summarizes cutting-edge biostrategies, ligninolytic enzymes, metabolic pathways, and lignin-degrading strains or consortia involved in lignin degradation, while critically evaluating the underlying mechanisms. Metabolic and genetic engineering play crucial roles in redirecting lignin and its derivatives towards metabolic pathways like the tricarboxylic acid cycle, opening up novel avenues for its valorization. Recent advancements in lignin valorization are scrutinized, highlighting key challenges and promising solutions. Furthermore, the review underscores the importance of innovative approaches, such as leveraging digital systems and synthetic biology, to unlock the commercial potential of lignin-derived raw materials as sustainable feedstocks. Artificial intelligence-driven technologies offer promise in overcoming current challenges and driving widespread adoption of lignin valorization, presenting an alternative to sugar-based feedstocks for bio-based manufacturing in the future. The utilization of available lignin residue for synthesis of high-value chemicals or energy, even alternative food, addresses various crises looming in the food-energy-water nexus.
木质素是一种富含能量且适应性强的聚合物，由苯丙烷类单体组成，植物利用其进行结构强化、水分运输和防御机制，它是地球上第二普遍的生物聚合物，仅次于纤维素。尽管其普遍存在，但在将生物质转化为燃料和化学品的过程中，木质素经常未得到充分利用。相反，由于其复杂的组成和抗分解性，它通常被焚烧以获取工业热量，这为有针对性的增值利用带来了障碍。与化学催化剂不同，生物酶不仅在选择性转化木质素成分方面显示出前景，而且能够无缝融入细胞结构，为木质素增强提供了一条潜在的高效生物催化途径。本综述全面总结了参与木质素降解的前沿生物策略、木质素分解酶、代谢途径以及木质素降解菌株或菌群，同时批判性地评估了其潜在机制。代谢工程和基因工程在将木质素及其衍生物导向三羧酸循环等代谢途径方面发挥着关键作用，为其增值利用开辟了新途径。对木质素增值利用的最新进展进行了审视，突出了关键挑战和有前景的解决方案。此外，该综述强调了创新方法的重要性，例如利用数字系统和合成生物学，以释放木质素衍生原料作为可持续原料的商业潜力。人工智能驱动的技术有望克服当前的挑战并推动木质素增值利用的广泛应用，为未来生物基制造提供替代糖基原料的选择。利用现有的木质素残渣合成高价值化学品、能源甚至替代食品，可应对粮食 - 能源 - 水关系中迫在眉睫的各种危机。
