Lignin biotransformation: Advances in enzymatic valorization and bioproduction strategies

Abstract

Lignin, the main component of the plant's cell wall and the most abundant aromatic macromolecule, is known for its resistance to degradation, therefore its valorization is a crucial stride towards fostering cleaner consumption and production. The applications of microbial ligninolytic enzymes for achieving efficient lignin biotransformation have gained much attention recently. This review summarized the structural characteristics of lignin which aids recalcitrance to its degradation, and the recent progress in harnessing ligninolytic enzymes for efficient lignin bio-depolymerization. This review discusses the evolution and engineering of ligninolytic enzymes with a particular focus on the role of artificial intelligence in revolutionizing enzyme engineering. Synthesis of lipids, aromatics, ring-opening compounds, and polyhydroxyalkanoate through lignin biotransformation is discussed to highlight its versatility as a source of value-added chemicals. The current state of knowledge, possible gaps, and future directions are also presented. The integration of structural understandings, enzymatic mechanisms, and downstream applications offers a holistic overview, making it a helpful resource for researchers in lignin valorization.