Structural transformation of hemicelluloses and lignin from triploid poplar during acid-pretreatment based biorefinery process

► Hemicelluloses and lignin were obtained by acid-based biorefinery process. ► The hemicelluloses backbone was obviously hydrolyzed, but the ester bonds remained. ► The cleavage of β-O-4 bond and C-C condensation were simultaneously occurred. ► The correlations from G units were shifted because of the formation of C-C bonds.