Engineering lignin pathway, plant cell wall modification, and genome editing for advanced renewable bioenergy and...

Lignin biosynthesis and plant cell wall engineering are central to plant structural integrity and biomass utility. Recent advances in molecular and synthetic biology have opened opportunities to tailor lignin contents, composition, and polymer structure for renewable bioenergy and sustainable biomaterial applications. This review provides an integrative perspective on biosynthesis, regulation, and engineering of lignin. It summarizes the current progress in understanding the genetic, transcriptional, epigenetic, and metabolic networks that control lignin formation, with a focus on emerging tools such as CRISPR/Cas genome editing, synthetic promoters, and metabolic rewiring. Beyond cataloguing current knowledge, it critically analyzes the trade-offs involved in lignin modification for biomaterials, addressing unresolved challenges such as monolignol transport, metabolic flux control, and species-specific regulatory divergence. Engineered lignin and modified plant cell walls hold significant potential for biorefineries, advanced polymers, pharmaceuticals, and carbon sequestration, yet their translation from the laboratory to the field remains limited. Engineered lignin offers real-world applications across diverse industries, including bioenergy, bioplastics, carbon fiber composites, pharmaceuticals, and sustainable construction materials, thereby reinforcing its pivotal role in advancing a circular bioeconomy. The review further proposes future research directions that integrate multi-omics, single-cell technologies, machine learning, and field-based validation to enable precision lignin engineering. Strategic advances in this field will support next-generation bioenergy systems, advanced biomaterials, and the transition to a circular bioeconomy.