11-33: Understanding how cell wall differences in agave, poplar, and switchgrass affect deconstruction in pretreatment and enzymatic hydrolysis

Agave has emerged as promising biofuels feedstock mainly because it offers high productivity with low water and nutrient demands on semiarid lands. However, our recent results indicated that agave is significantly less recalcitrant than typical lignocellulosic feedstocks such as poplar and switchgrass. Systematic understanding of structural differences in agave, poplar, and switchgrass and the consequences on cell wall deconstruction can provide clues on paths to reduce recalcitrance that is the key impediment to large-scale commercialization of processes for making fuels from cellulosic biomass. Thus, our high throughput pretreatment and hydrolysis (HTPH) system was used to evaluate the effect of hydrothermal pretreatment conditions and enzyme formulations on sugar yields for four agave materials along with poplar and switchgrass. At the same time, a series of characterization techniques were employed to compare the structural differences in cell walls, including lignin composition, non-cellulosic wall components and extractability, cellulose crystalline structure, and surface accessibility.  These studies identified important structural features that contribute to lower recalcitrance of agave species and suggested promising directions for more cost effective deconstruction of plant cell walls.