Fig. 3

Identified lignocellulose types in various biomasses. a Simplified schematic of cell wall polysaccharides, including cellulose, hemicellulose, and pectin. Only the glycosidic oxygens are shown while hydroxyl groups are omitted for clarity. Panel adapted with permission of ref [61]. b Schematic representation of the lignin structure, highlighting its three primary monomeric units: p-hydroxyphenyl (H, orange), guaiacyl (G, pink), and syringyl (S, brown). Ferulate (FA, light orange) and p-coumarate (pCA, cyan) are additional lignin-associated phenolic units predominantly found in grasses, typically ester-linked to hemicelluloses and lignin. The most common inter-unit linkages are emphasized in blue. Panel adapted with permission of ref [62]. c Schematic representation of the suberin structure, illustrating its aliphatic chains (blue) and lignin-like phenolic (yellow) compounds. Monomer units are shown with corresponding ¹³C chemical shifts labeled for each carbon site, with shifts derived primarily from references [34, 63,64,65,66]. d The relative abundance of cellulose, hemicellulose, and lignin, along with lignin compositional differences in each biomass, is shown