A systems view of lignocellulose hydrolysis

With a growing need to produce low-carbon fuels and chemicals for sustainable economic development, there is growing interest in utilizing lignocellulosic biomass as a feedstock resource for the emerging bioeconomy. Lignocellulosic biomass is currently available in large quantities as crop and forest residues or organic wastes, and could be produced at high yields by planting dedicated energy crops, but is not as easily processed by biochemical or thermochemical conversion technologies as other bio-based feedstocks such as sugars, starches, or oils. Many approaches to utilizing lignocellulosic resources and converting them into value added products first require deconstruction the plant cell wall polymers into their constitutive sugars for fermentation or chemical conversion, and often recover lignin as a co-product. This process of plant cell wall deconstruction, or hydrolysis, includes both pretreatment technologies that degrade the lignin, and saccharification technologies that produce sugar monomers and oligomers from sugar polymers such as cellulose and hemicellulose. This chapter reviews leading technologies for deconstructing lignocellulosic biomass, including mechanical, chemical, and biological approaches, and evaluates the advantages and tradeoffs among them.