Structural sugar profile of fiber residues from high-cannabinoid type hemp and potential for value-added fermentation

U.S. production of hemp (Cannabis sativa L.) has been largely driven by the cannabidiol (CBD) market. Processing of high-CBD type hemp results in large amounts of unused lignocellulosic biomass. There has been substantial interest in the use of this fibrous residue for production of bio-based materials and for replacement of petroleum-based chemicals. Unlike stalks from industrial fiber or grain hemp, high-CBD hemp stalks are not well suited for decortication. Instead, this material is typically milled as a single stream, such that the bast and hurd fibers are combined. Little information is available on the composition of the structural sugars in these kinds of whole milled hemp fibers. Such information that is needed to evaluate the feasibility of pretreating the fiber for enzymatic hydrolysis and downstream fermentation of the C5 and C6 sugars. Additionally, the mixed fiber biomass from high-CBD hemp is expected to closely resemble the biomass residues from the recreational and medicinal Cannabis industries. The goal of this research is to characterize the fiber residues from high-CBD hemp in order to gauge the potential for value-added fermentation of the waste streams from these growing markets.