Xiaohui Ju, Elvie Brown, Xiao Zhang
School of Chemical Engineering and Bioengineering
Washington State University
A deeper understanding of “biomass recalcitrance” is a key to the development of cost effective pretreatment methodologies and discovery of highly efficient cell wall polysaccharide degrading enzyme systems. A considerable amount of research effort has been directed to delineating the relationship between specific biomass substrate properties, such as cellulose crystallinity and lignin content, and the efficacy of cellulase enzyme components. However, 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 any individual characteristic (e.g. cellulose DP, crystallinity, lignin and hemicellulose content, available surface area) on enzymatic hydrolysis without interference from other substrate parameters. Chemical pulping is a well established biomass fractionation technology with the objective to remove lignin and produce intact fibers for papermaking. Unlike most biomass pretreatment methods which lead to random disruption of the fiber cell wall, chemical pulping technologies have been developed to selectively dissolve lignin while maintaining the integrity of cellulose fibers.
In this presentation, we will discuss our approach to apply chemical pulping methodology to create a set of biomass substrates, “reference substrates” which will systematically represent the major key biomass characteristics at the fiber, fiber topographic, fibril and molecular levels. The performance of several cellulase enzymes on some of the reference substrates will also be discussed.