Lignin Utilization Technology Session Review Area: Biochemical Conversion & Lignin Utilization PI: Gregg T. Beckham, National Renewable Energy Laboratory From Davis et al. NREL Design Report 2013; Project overview Corona et al. Green Chem. 2018 Goal: Develop industrially-relevant processes and tools for Heilmeier Catechism: viable lignin valorization – contribute $2-3/gge to MFSP • Aim: develop lignin depolymerization catalysts and • Develop deconstruction catalysts for C–C bonds in lignin analytics for accurate process metrics • Provide deconstructed lignin to bioconversion efforts • Today: lignin combusted for heat, C–C bonds are • Develop lignin analytics and model compound syntheses major hurdle, analytics mostly monomers only • Support lignin projects in the BETO/DOE portfolio • Important: lignin key for biorefinery TEA and LCA (Biological Lignin Valorization (BLV), LigFirst, ORNL • Risks: C–C cleavage and quantitative lignin project, SepCon, Bioenergy Research Centers, etc.) analytics are both challenging NREL | 2 Management Task 1: Analytics and Synthesis • Experts in synthesis (R. Katahira) and analytics (B. Black) • Milestones: lignin characterization tool development, model compound synthesis • Collaborate with multiple projects – support BETO lignin portfolio for analytics and models Task 2: Depolymerization • Experts in oxidation catalysis (X. Du, C. Palumbo, K. Sullivan) and chemical engineering (J. Kruger) • Milestones: usable monomer yield from oxidative catalytic deconstruction processes • Milestones: reaction/process engineering, TEA/LCA with Biochem. Analysis, integration with BLV project Project organization: • Monthly meetings for catalysis and analytics • Monthly 1-on-1 mtgs with PI, staff, postdocs • Ad hoc meetings with Lignin-First Biorefinery Development, Biological Lignin Valorization, SepCon, Analysis, and other projects • Ops and Project Managers – labs, equipment, reporting, and finances NREL | 3 Management: Project interactions Projects interchange We have established a network of lignin-related projects with Lignin Utilization as the central project Lignin • Provide analytics development and support, model compound Corn stover Low temperature advanced Utilization syntheses, and central lignin valorization platform for: deconstruction o Lignin-First Biorefinery Development Separation Lignin Deacetylation Consortium o Biological Lignin Valorization liquor o Low-Temperature Advanced Deconstruction, Feedstock- Conversion Interface Consortium Synthetic Metabolic Pathways for Bioconversion of Lignin Mechanical o refining Derivatives to Biofuels– ORNL o Synthesis and Analysis of Performance-Advantaged Bioproducts Monomers & Lignin Enzymatic Bioavailable o Separations Consortium hydrolysis solids molecules Risks: • Oxidative C–C bond cleavage is an inherently challenging Soluble Biological Lignin Valorization reaction sugars • Oxidative reactions with lignin often lead to undesired side reactions Performance advantaged bioproducts • Quantitative lignin analytics long pursued, not definitively/generally demonstrated NREL | 4 Approach Overall approach: • Catalyst development focuses on oxidative MFSP ($/GGE), Base Case = $2.49 catalysis to cleave C–C bonds and produce bio- Total capital investment (TCI) available aromatic compounds (SepCon, BLV) Metabolically accessible lignin (wt%) Muconic productivity (g/L/hr) Pertraction butyric acid recovery (wt%) • Analytics and synthesis disseminate methods CEH Solids loading (wt%) via Laboratory Analytical Procedures DMR NaOH loading (mg/g) Feedstock Cost ($/dry ton) DMR xylan to liquor (wt%) • Work with Biochem. Analysis project to develop Sugar diversion to coproduct (wt% clean sugar) Fermentation glucose to product (wt%) TEA cases towards 2030 for lignin valorization Muconic metabolic yield (g/g sugar) Muconic acid hydrogenation Temperature (°C) Fermentation xylose to product (wt%) Acid catalysis train capital cost DMR lignin to liquor (wt%) Muconic acid fermentation pH control Major milestones, Go/No-Go Decisions: Enzyme production capital cost Fermentation Productivity (g/L/hr) • FY20: Screen 15 oxidation catalysts for C–C CEH cellulose to glucose (wt%) Fermentation arabinose to product (wt%) bond cleavage in model compounds CEH xylan to xylose (wt%) • FY21 G/NG: 20% above C–O bond cleavage $0.00 $0.20 $0.40 $0.60 $0.80 $1.00 baseline for a catalytic oxidation process ($1.00) ($0.80) ($0.60) ($0.40) ($0.20) • FY22 (end of project): 60% monomer yield from lignin via C–O and C–C bond cleavage NREL | 5 B.A. Black, X. Dong, H.B. Approach: Analytics Mayes, et al. in preparation Goal: Rapidly identify dimeric and oligomeric compounds in lignin samples LC-MS optimization for Lignin-based compound rich data generation library generation Challenges: • Existing methods need standards to develop frag. patterns, limited for high-fidelity compound ID • Existing MS analyses rely on compound libraries that do not include lignin-derived compounds Experimental effort Computational effort Approaches: in LigU in Biochemical Process Modeling • Determine approaches that can differentiate lignin- and Simulation derived molecules (BPMS) • Build on previous modeling efforts1-3 to generate a comprehensive lignin-based compound library • Pattern match experimental fragmentation data with computational library to rapidly identify compounds Identification by NREL | 6 1. Orella et al. ACS SusChemEng 2019; 2. Gani et al. ACS SusChemEng 2019; 3. Vermaas et al. ACS SusChemEng 2018 substructure matching Approach: Metal-catalyzed oxidation of lignin Goal: Develop C–C bond cleavage catalysis to depolymerize lignin oligomers Lignin Corn stover LTAD or Lignin- First project Utilization Challenges: Separation Liquor (or Deacetylation Consortium • C–C bonds difficult to cleave due to their stability RCF oil) • Phenolic moieties of lignin deactivate catalysis Mechanical • Currently no selective methods to achieve high refining monomer yields through oxidation of lignin Monomers & Enzymatic Lignin Bioavailable hydrolysis solids molecules Approaches: Soluble Biological Lignin Valorization • POM-mediated oxidative cleavage of C–C bonds sugars • Metal-mediated autoxidation for C–C bond cleavage Performance advantaged • Base-catalyzed depolymerization, with recovery and bioproducts regeneration of salts NREL | 7 Impact Scientific: • Monomer yields are limited: C–C cleavage studies will be impactful • Lignin-related computational pipelines published as open-source online via GitHub • Developing quantitative methods for lignin analytics and process performance metrics Industrial: • Analytics is a common request – multiple Technical Services Agreements & CRADAs • Partnership with oil major for advice on oxidation catalysis at scale, towards commercially relevant processes • Focused on both DOE-relevant lignin substrates (DMR- EH) and pulp & paper lignins (Kraft) Overall: LigU aims to enable quantitative lignin characterization and achieve high-yield deconstruction chemistry for the biorefinery NREL | 8 Progress and Outcomes Outline of technical accomplishments and ongoing and future work • Model compound syntheses • MS method development for comprehensive lignin characterization • Computational-experimental pipeline for rapid and quantitative lignin characterization • Polyoxometalate-catalyzed lignin oxidation • Metal-catalyzed lignin oxidation • Base recovery in lignin depolymerization NREL | 9 Model compound synthesis β β α -O-4 β 4 -O-4 with C =O O OMe OH β 4 β 4 β 4 O β 4 α β O β O 4 O O 4 α β α α γ O 4 α HO OH OH OMe 1 2 3 (HH) 4 (GG) 5 (SS) 6 7 8 (GG) β-1 with CαOH OMe OMe β-1 with HO γ HO HO HO β β β β β β OH OMe HO 1 HO 1 HO 1 OMe HO 1 OMe 1 1 OH OH CαOH α β β CγOH β 1 1 OH OH OH OH 1 HO MeO OMe OMe OMe OMe OH OH OH OH 9 10 11 12E (Erythro) 12T (Threo) 13E (Erythro) 13T (Threo) 14E (Erythro) 14T (Threo) Stilbene OMe OMe 5-5’ R1: H, OMe OH OH Cinnamyl OH OMe alcohol HO MeO R1 5 5’ R1 R1 5 5’ R1 R1 5 5’ R1 MeO 5 5’ OMe OMe OMe OH OH OH OH OH OH OH OH 15 16 17 18/19 20/21 22/23 24 25 (H) 26 (G) 27 (S) OH Bibenzyl OMe OMe RCF R1: OH, OMe β-5 β-β OH OMe Std 5 β β β HO MeO R1 OMe MeO OMe R1 OMe OMe OMe OH OH OH 28 29 30 31/32 33 34/35 36/37 38 39 Epoxide OMe OMe • Prepared 42 models as substrates for catalytic, biological, and stereo-chemically O specific lignin depolymerization testing and as analytical standards MeO • Enabled multiple biological and catalytic studies for lignin valorization OMe NREL | 10 40 41 42 across the DOE lignin project portfolio and for many collaborators Lignin analytics: new MS methods for lignin characterization Goal: Develop methods that provide X. Dong, B.A. Black et al. in review at Green Chem. improved data for confident lignin oligomer identification resonance-MS2 286 Parent ions accelerated 2 β-O-4 [M-H+]- Conventional MS methods are limited ✓ 331 β-5 for lignin identification − ✓ β-β ✓ Tandem MS at a single collision energy − 5-5 x ? • Results in limited structural information for 4-O-5 x 316 Product ions not 271 e.g. 5-5, 4-O-5, and β-1 linkages accelerated β-1 x one optimal collision energy (0.8 V) Energy resolved MS (ERMS) methods [M-H+]- OH 331 93 beam-ERMS 137 Tandem MS at multiple collision energies OH β-O-4 • Increase in fragmentation with beam- ✓ O O O O configured instruments for maximum All ions accelerated β-5 ✓ β-β 301 structural info ✓ 163 316 − − − − 5-5 • Allows for ID of lignin oligomers from 6 ✓ 151 4-O-5 ✓ major linkages β-1 ✓ Beam-ERMS methods allow for identification of all lignin oligomers NREL | 11 Lignin analytics: library development and