Characterizing cell wall crosslinking and/or entanglement in reduced recalcitrance feedstocks

The cell wall of plants is composed up of a variety of biopolymers including lignin, hemicellulose, pectin, and cellulose.  When these polymers are deconstructed to monomeric sugars, they can be utilized to produce fuels and chemicals.  However, this is processes of breaking down these polymeric components to their monomers, can be difficult due to the recalcitrant nature of lignocellulosic material.  Understanding how the properties of the biopolymer matrix, such as crosslink density and/or entanglement, are affecting recalcitrance is vital to engineering plants for improved biofuels production and performance.  In this work we have investigated solvent swelling experiments and T₂ NMR relaxation measurements to begin to correlate cell wall polymer mobility with recalcitrance.  Since lignin has been shown to play a major role in recalcitrance, plant systems with changes in their lignin content and structure have been selected for these studies.  The effects of down regulation in p-coumarate 3’ hydroxylase (C3H), cinnamate-4-hydrolylase (C4H) and shikimate hydroxycinnamyol transferase (HCT) in the lignin biosynthetic pathway on biopolymer mobility will be discussed.