Mechanisms employed by cellulase systems to gain access through the complex architecture of lignocellulosic substrates.

To improve the deconstruction of biomass, the most abundant terrestrial source of carbon polymers, en route to renewable fuels, chemicals, and materials more knowledge is needed into the mechanistic interplay between thermochemical pretreatment and enzymatic hydrolysis. In this review we highlight recent progress in advanced imaging techniques that have been used to elucidate the effects of thermochemical pretreatment on plant cell walls across a range of spatial scales and the relationship between the substrate structure and the function of various glycoside hydrolase components. The details of substrate and enzyme interactions are not yet fully understood and the challenges of characterizing plant cell wall architecture, how it dictates recalcitrance, and how it relates to enzyme-substrate interactions is the focus for many research groups in the field. Better understanding of how to match pretreatments with improved enzyme mixtures will lead to lower costs for industrial biorefining.