Molecular-level driving forces in lignocellulosic biomass deconstruction for bioenergy

The plant cell wall biopolymers lignin, cellulose and hemicellulose are potential renewable sources of clean biofuels and high-value chemicals. However, the complex 3D structure of lignocellulosic biomass is recalcitrant to deconstruction. Major efforts to overcome this recalcitrance have involved pretreating biomass before catalytic processing. This Perspective describes recent work aimed at elucidating the molecular-level physical phenomena that drive biomass assembly. These are at play in commonly employed aqueous-based and thermochemical pretreatments. Several key processes have been found to be driven by biomass solvation thermodynamics, an understanding of which therefore facilitates the rational improvement of methods aimed at the complete solubilization and fractionation of the major biomass components. This Perspective describes the physical molecular driving forces that stabilize native lignocellulosic plant biomass structures and govern thermochemical biomass pretreatments. Understanding these driving forces can help us to design efficient methods for deconstructing biomass into biofuels and other bioproducts.