Fine-tuning xylan side chains for enhanced production of high-yield sugars, fine-shaped nanocrystals, and stable Pickering emulsions in Arabidopsis thaliana.

Abstract

Arabinoxylans are complex polysaccharides found in the secondary cell walls of plants, and their substitution patterns of arabinose (Ara) and glucuronic acid (GlcA) significantly affect their properties for structural and bio-functional applications. In this study, we engineered xylan side chains by overexpressing the arabinosyltransferase AtXAT2 in both wild-type Arabidopsis and a glucuronic acid-deficient mutant (atdgux). The genetically modified xylan substrates were subsequently utilized to prepare nanocrystals and Pickering emulsions. Notably, nanocrystals derived from lower-substituted xylan displayed more ordered arrangements and higher crystallinity, while conventional xylan substrates exhibited superior emulsifying properties. Furthermore, the modification of xylan side chains significantly influenced the alignment and crystallinity of cellulose microfibrils, enhancing biomass saccharification and reducing cellulose nanocrystal dimensions. This study thus illustrates an effective strategy for achieving diverse and valuable bioproduction through precise genetic engineering of xylan in plants and provides valuable insights into the dynamic mediation of xylan and the construction of cell wall networks.