Advancing the National Bioeconomy through Regional Sun Grant Centers-

Lignin�]first biorefining will enhance the bio�]economy by capturing valuable lignans (phenolic compounds with anti�]inflammatory and antioxidant properties) prior to further processing of agricultural and forest residues to biofuels. Our model system, white oak sawdust (WOS), is a waste byproduct from cooperages supplying barrels to the bourbon industry in Kentucky. Syringaresinol, a lignan with anticancer properties, is an extremely high�]value product (selling for hundreds of dollars per mg) that can be recovered unsustainably from white oak with organic solvents. This project will develop a green chemistry lignin�]first separation strategy to obtain a high value coproduct from an existing forest byproduct. A generalizable approach to targeting high�]value secondary metabolites found in native plants through molecular recognition will be developed. As our understanding of the therapeutic efficacy of plant�]derived lignans develops,4 so too will economic opportunities associated with their isolation and production. Syringaresinol, a dimer of two lignin syringyl units linked with a ƒÀƒÀ bond (S�]ƒÀ�]ƒÀ�] S), exists in relatively large amounts (partially glycosylated) in white oak. Current approaches to pretreat WOS for biofuel production renders S�]ƒÀ�]ƒÀ�]S unusable. We propose a process of extracting S�]ƒÀ�]ƒÀ�]S from WOS in an acidic ethanol/aqueous solution prior to pretreating for biofuel production. S�]ƒÀ�]ƒÀ�]S will be selectively recovered from the aqueous stream using cyclodextrin (CD)�]functionalized particles, where CD forms a host�]guest complex with lignan dimers. The mission of the Sun Grant Initiative is to develop viable alternative bioderived energy sources and products while enhancing rural economic opportunities. This project will develop novel methods for selective isolation of high�]value therapeutic co�]products from lignocellulosic biomass, which has been shown to allow competitive ethanol production from cellulosic biorefineries.1 For instance, recovering a pharmaceutical with a value of $300/kg allows the biorefinery to achieve the current target $2.50/gal ethanol price2 with established lignocellulosic technology. 2 | P a g e This project is important to the Southeastern Sun Grant because white oak is the dominant hardwood species in the US, and is concentrated in the central hardwood region including Kentucky, Tennessee, Mississippi, and Alabama. Correspondingly, white oak barrels represent approximately 1/3 of Kentucky�fs wood�]related exports ($100Mof $347M in 2017). Integrating sustainable technologies to upgrade low�]value byproducts of white oak production can provide economic benefits to this region. This research addresses priority areas of sustainability (deriving value added products from waste streams) and new bioderived products (energy, chemicals or materials) in the production of therapeutic lignans. The feedstock priority is woody biomass, specifically white oak. The selective recovery of S�]ƒÀ�]ƒÀ�]S lignans from WOS will be demonstrated using the following: Specific Aim 1 .The capacity and selectivity of S�]ƒÀ�]ƒÀ�]S lignan capture from aqueous ethanol streams using micron�]sized CD�]functionalized silica particles will be determined by solution depletion studies. Chemical analysis of model and real aqueous solutions from the extraction of WOS before and after CD binding will be used to determine how effectively silica�]bound CD complexes with S�]ƒÀ�]ƒÀ�]S, and guide the development of advanced silica adsorbent materials for molecular recognition. Specific aim 2 .Isolation of S�]ƒÀ�]ƒÀ�]S on columns will be investigated to demonstrate its recoverability from CD�]functionalized silica adsorbent and move toward commercial feasibility. Fused silica capillary columns will be packed with CD�]modified silica particles. Loading isotherms and column break�]through measurements will be used to characterize the kinetics of the CD : S�]ƒÀ�]ƒÀ�]S interaction, providing design details to establish a scalable commercial system. Specific aim 3 . White oak sawdust both before and after the extraction of S�]ƒÀ�]ƒÀ�]S will be pretreated and then hydrolyzed. The hydrolysate will be analyzed to determine if 3 | P a g e removing S�]ƒÀ�]ƒÀ�]S conserves, enhances, or reduces the accessibility of carbohydrates in the white oak sawdust. Expected deliverables: Deliverables include 2 refereed journal articles, 2 research presentations at national scientific conferences, and 3 S�]1075 multi�]state annual reports. Who will benefit and how? The WOS byproduct producers will benefit from this technology, as will the rural communities in which they are located; they are typically located in rural communities. References: 1. Yang, M.; Baral, N. R.; Simmons, B. A.; Mortimer, J. C.; Shih, P. M.; Scown, C. D., Accumulation of High�]Value Bioproducts in Planta Can Improve the Economics of Advanced Biofuels. Proceedings of the National Academy of Sciences 2020, 117, 8639�]8648. 2. Schwab, A., Bioenergy Technologies Office Multi�]Year Program Plan; US DOE Office of Energy Efficiency and Renewable Energy, 2016. 3. Peplow, M., Looking for Cheaper Routes to Malaria Medicines. Chemical and Engineering News 2018, 96, 29�]31. 4. Yeung, A. W. K., et al., Lignans: Quantitative Analysis of the Research Literature. Front Pharmacol 2020, 11, 37�]37.