biostudies-literatureWang YNational Natural Science Foundation of China18861-18869https://www.ebi.ac.uk/biostudies/studies/S-EPMC9178751biostudies-literatureUnknown7(22)Lignin is a natural aromatic compound in plants. Several lignin structural models have been proposed in the past years, but all the models cannot be converted to benzene carboxylic acids (BCAs) for all aromatic rings connected to oxygen. This inspired us to explore the structures of lignin. Based on the yields of BCAs, the results of ¹³C NMR and ethanolysis residues, and gas chromatography-mass spectrometry and electrospray ionization mass spectrometry of ethanolysis of lignin, we have constructed a structural model of lignin with a formula C₆₄₀₇H₆₇₃₆O₂₅₉₀N₁₄₇S₃. The model not only satisfies the results of analyses, but also explains the generation of BCAs from lignin oxidation and the ethanolysis products. Importantly, double-ring and triple-ring aromatic clusters are found in lignin, and some of them are connected by alkyl bridges, which results in conventional low conversions of lignin. Our findings in the structures of lignin may significantly influence the structures and applications of lignin.ACS omegaA New Structural Model of Enzymatic Lignin with Multiring Aromatic Clusters.PMC91787512217801721776199Li HLi JWang YWu WHou YRen SfalseA New Structural Model of Enzymatic Lignin with Multiring Aromatic Clusters.Lignin is a natural aromatic compound in plants. Several lignin structural models have been proposed in the past years, but all the models cannot be converted to benzene carboxylic acids (BCAs) for all aromatic rings connected to oxygen. This inspired us to explore the structures of lignin. Based on the yields of BCAs, the results of ¹³C NMR and ethanolysis residues, and gas chromatography-mass spectrometry and electrospray ionization mass spectrometry of ethanolysis of lignin, we have constructed a structural model of lignin with a formula C₆₄₀₇H₆₇₃₆O₂₅₉₀N₁₄₇S₃. The model not only satisfies the results of analyses, but also explains the generation of BCAs from lignin oxidation and the ethanolysis products. Importantly, double-ring and triple-ring aromatic clusters are found in lignin, and some of them are connected by alkyl bridges, which results in conventional low conversions of lignin. Our findings in the structures of lignin may significantly influence the structures and applications of lignin.2022-01-01T00:00:00Z2022 Jun2025-04-04T03:05:54.276Z2025-02-19T05:06:19.84ZS-EPMC91787513569451810.1021/acsomega.2c01812