(503c) Alkaline Pretreatment to Fractionate Industrial Hemp for Biochemical Conversion and the Effects on Polysaccharide and Lignin Recovery

The passage of the 2018 Farm Bill in the United States directed the USDA to establish national regulations for the cultivation of industrial hemp in the U.S. This has allowed agricultural producers to start growing industrial hemp to be used in new application routes as a feedstock for bio-based fuels and chemicals. The previous restrictions on planting and harvesting hemp have not allowed this feedstock to be sufficiently researched in the context of biochemical conversion compared to other lignocellulosic crops such as woody biomass or perennial grasses. Thus, the aim of this research is to provide a more thorough understanding on the deconstruction of industrial hemp to access both polysaccharide and lignin fractions. In this work industrial hemp was pretreated using alkaline chemistry to determine the effect on both hemicellulose and lignin removal. Increasing chemical severity confirmed that cellulose content was maintained after pretreatment, but hemicellulose and lignin removal increased under the same conditions. Enzymatic hydrolysis of the pretreated hemp produced high yields of sugar recovery (i.e. glucose and xylose) to generate a hydrolysate media for downstream fermentation. The resulting pretreatment liquor was utilized as a source for lignin separation and recovery. The recovered hemp lignin from pretreatment underwent chemical characterization using microscale analytical pyrolysis to characterize constituent monomeric components.