A Quantitative Determination of the Effects of Surface/Bulk Lignin and Xylan Contents On Enzymatic Hydrolysis of Lignocellulosic Biomass

Lignocellulosic biomass provides an abundant source of sugars for sustainable biofuels and biochemical production. However, the lack of highly efficient and cost effective cell-wall degrading enzymes is a major obstacle preventing the commercialization of a biologically based lignocellulosic biomass conversion process. The effectiveness of enzymatic hydrolysis is inextricably linked to the structural and chemical characteristics of the biomass material. Due to the diverse nature of lignocellulosic biomass and the heterogeneous structural and chemical characteristics of pretreated biomass substrates, it is difficult to investigate the effect of individual substrate characteristic on enzymatic hydrolysis. We have developed a new methodology based on chemical pulping principles to create a set of biomass “reference substrates” with controlled properties to reflect chemical and structural diversity of biomass materials. The individual effects of surface/bulk lignin and xylan contents on enzymatic hydrolysis of these substrates were determined.

X-ray photoelectron spectroscopy (XPS) has been demonstrated as an effective tool to investigate the surface lignin content and its effect on enzymatic hydrolysis. A Response Surface Methodology (RSM) was employed to attain an aggregated understanding of surface/bulk lignin and xylan contents influence on biomass recalcitrance.