Lignin key role in increased saccharification of CAD-downregulated poplar wood

In our study, for the first time, dilute acid pretreatment (DAP) was applied under different severity conditions to poplar wood genetically modified for the CAD1 gene. The carefully selected pretreatment conditions resulted in glucose yields that were 15 points higher for this modified genotype than for the wild-type (WT) wood after 48 h of enzymatic hydrolysis.

To explain this higher saccharification rate, the chemical, spectral and structural changes in WT and CAD wood were analyzed in relation to the severity of the pretreatment process. Although few differences were found at the chemical level, variations in autofluorescence and cell deformation were more significant: at high severity, the cells of CAD wood observed by nanotomography were more easily deformed, but their middle lamella was more resistant than those of WT wood. All these differences are possibly explained by changes in the molecular structure of lignin in CAD wood, leading to the formation of more hydrophobic shorter monomer chains with fewer lignin‒carbohydrate interactions.

This work is part of the PhD thesis of Julien du Pasquier which is a project between the Biotechnology Chair of CentraleSupélec and FARE lab, in collaboration with BioForA lab.

du Pasquier J, Zoghlami A, Naudin Y, Déjardin A, Pilate G, Paës G*, Perré P*. Cinnamyl alcohol dehydrogenase downregulation in poplar wood increases saccharification after dilute acid pretreatment: a key role for lignin revealed by a multimodal investigation. Biotechnology for Biofuels and Bioproducts 2025, 18, 30. http://doi.org/10.1186/s13068-025-02623-8

Contact: Dr Gabriel Paës, gabriel.paes@inrae.fr