Total Utilization of Miscanthus Biomass, Lignin and Carbohydrates, Using Earth-Abundant Nickel Catalyst

Scientific Achievement• All three major components of biomass (lignin, cellulose

and xylan) are converted in two steps into high value chemicals with an overall 55% yield.

Significance and Impact• Lignin as a natural aromatic polymer has great potential

to be a source for liquid fuels and chemicals. Its selective conversion is key to the viability of future biorefineries.

• Our study demonstrates a method for transforming 69% of the lignin in Miscanthus into four aromatic compounds while separating the carbohydrate components as a solid primed for upgrading.

Hao Luo, Ian M. Klein, Yuan Jiang, Hanyu Zhu, Baoyuan Liu, Hilkka I.Kenttämaa, and Mahdi M. Abu-Omar “Total Utilization of MiscanthusBiomass, Lignin and Carbohydrate, Using Earth Abundant Nickel Catalyst” ACSSustainable Chem. Eng. (2016). [10.1021/acssuschemeng.5b0177]Yuan Jiang, Linan Yang, Christine M. Bohn, Guannan Li, Dong Han, Nathan S.Mosier, Jeffrey T. Miller, Hilkka I. Kenttämaa, and Mahdi M. Abu-Omar.Speciation and Kinetic Study of Iron Promoted Sugar Conversion to 5-Hydroxymethylfurfural (HMF) and Levulinic Acid (LA) Org. Chem. Front., 2,1388-1396, (2015). [10.1039/C5QO00194C]Work was performed at Purdue

Research Details‐ Reaction of Miscanthus biomass in alcohol solvent at 200 °C

and 30 bar pressure results in fragmentation of lignin into soluble oligomers.

‐ Nickel catalyst supported on activated carbon depolymerizes lignin (CDL) fragments and deoxygenates (HDO) them to yield four phenolic products.

‐ The leftover carbohydrate byproduct (solid residue) is reacted in a second step in biphasic medium with iron chloride catalyst to make furfural and levulinic acid.

Biomass accessibility analysis using electron tomography

Scientific AchievementDeveloped new method for quantifying catalyst accessibility to biomass using 3D electron tomography.

Significance and Impact‐ Our characterization over range of <5nm

to >100nm catalyst sizes not possible with existing accessibility measures

‐ Image‐based method suggests mechanisms for increased accessibility as opposed to bulk measures

‐ Quantify threshold where bottlenecks erase accessibility improvementsResearch Details

‐ Pore network is summarized by computing distance contour tree using segmented 3D tomograms

‐ Efficient algorithm allows computing large range of catalyst sizes on large volumes

‐ Analyzed native, dilute acid + zipperclave, and dilute acid + steam explosion treated samples.

Hinkle J; Ciesielski P.N; Gruchalla, K; Munch, K; Donohoe, BS. Biomass accessibility analysis using electron tomography. Biotechnology for Biofuels, 8, 212 (2015). [10.1186/s13068-015-0395-8]Work was performed at NREL

Surface Accessibility vs Catalyst Radius

Segmented Tomograms

Volumetric Accessible Radius

Surface Map of Accessible Radius

Targeting iron catalysts to cellulose microfibrils

Scientific Achievement‐ Proof-of-concept that we can tailor biomass to incorporate

chemical catalysts in living plants.

Significance and Impact‐ Iron ions are inexpensive, earth‐abundant catalysts that

defibrillate and delaminate cell wall structure when used in pretreatments.

‐ By engineering plants to accumulate iron in their cell walls, the catalyst can be used at less than thousand‐fold lower concentrations than for exogeneous treatments.

‐ Biomass yield is not compromised in transgenic plants.Citation: Yang et al. (2016) Plant Biotechnology Journal, pp1-12, doi: 10.1111/pbi.12557Work was performed at Purdue University and NREL

Research Details‐ We engineered CBM‐IBP fusion polypeptides composed of a

carbohydrate‐binding module family 11 (CBM11) and an iron binding peptide (IBP) for secretion into Arabidopsis and rice cell walls.

‐ Shoot iron concentrations in cell walls, release of glucose by hydrolases, and amounts of dry biomass are increased compared to control genotypes.

ArabidopsisRice

Lignin deposition impacts cellulose organization in the plant cell wall

Scientific Achievement‐ Direct demonstration that altering lignin content alters the

molecular organization of cellulose in plant cell walls

‐ Significance and Impact‐ Assembly of plant cell walls is a complex process.

Perturbation of one component may alter final structure in unexpected ways

‐ Lignin deficiency led to decrease in the order and orientation of cellulose fibrils in cell walls

‐ Distinctions between tissues were maintained in all variants even those with dramatic changes in cellulosic order

‐ The resilience of cellulose to degradative processes was much lower in plants rich in aldehyde‐ or H‐lignin

‐ Engineering of lignin composition may provide route to plants with lowered recalcitrance to deconstruction

Liu, J., J.I. Kim, J.C. Cusumano, C. Chapple, N Venugopalan, R.F. Fischetti and L. Makowski The impact of alterations in the lignin biosynthetic pathway on molecular architecture of the plant cell wall. Biotech. for Biofuels 9, 126‐143, (2016). [10.1186/s13068‐016‐0540‐z]Work was performed at Northeastern University, Purdue University and ArgonneNational Laboratory

Research Details‐ 16,000 diffraction patterns to study 7 Arabidopsis variants ‐ Combination of plant biochem and x‐ray biophysics‐ Correlation of structural change and digestibility‐ Importance of serendipity in research

Some interesting visual thing

A thin section of Arabidopsis stem was scanned past a 5 µ x‐ray beam to collect full diffraction patterns at each raster point. This generated a rich data set used to extract detailed information about cellulose order, orientation and content within the tissues that make up the stem.

Stereoselective synthesis of lignin models to probe lignin deconstruction and conversion

Scientific Achievement‐ An efficient stereospecific synthesis of lignin model dimers and

trimers has been achieved

Significance and Impact‐ Although lignin is optically inactive, biosynthesis leads to localized

stereochemical differences‐ Multiple biochemical processes show different rates of reaction with different

lignin stereoisomers‐ Localized stereochemical differences could be used for targeted deconstruction

of lignin‐ Access to stereochemically defined models to probe these differences is

difficult‐ Our approach offers access to both dimeric and trimeric lignin models‐ Computational modeling reveals different conformational preferences for

different isomers

Enantioselective Syntheses of Lignin Models - An Efficient Synthesis of β-O-4 Dimers and Trimers Using the Evans Chiral Auxiliary. Costyl N. Njiojob, J. J. Bozell, B. K. Long, T. Elder, R. E. Key, W. T. Hartwig, Chem. Eur. J. 2016, in press

Performed at the University of Tennessee Center for Renewable Carbon

Research Details‐ Two approaches to synthesis; most recent version uses an Evans

chiral auxiliary as the key step‐ First approach (J. Org. Chem. 2015, 80, 1771‐1780) required 9 steps;

new approach sets stereochemistry in only 5‐ Combination of two approaches leads to lignin trimer

R,R/S,S

R,S/S,R

Research Details‐ 13C NMR spectra indicate that maleic acid stabilizes the

open‐chain form of glucose to facilitate isomerization ofglucose to fructose.

‐ The catalyst complex converts fructose to HMF 1.7×faster and with 3.3× higher selectivity than a mixture ofHCl and AlCl3 at 180oC.

‐ Improved selectivity of glucose to HMF and levulinic acidlowers cost.

Scientific AchievementWe synthsized a dual-function catalyst that can convert glucose to HMF, a fuel and chemical intermediate, in one pot with higher selectivity.

Significance and ImpactMaleic acid (MA) and AlCl3 self-assemble intocatalytic complexes that lower the activation forthe rate limiting step (isomerization glucose tofructose) and enhances the selectivity ofconverting fructose to HMF and levulinic acidconversion.

Zhang, Ximing; Murria, Priya; Jiang, Yuan; Xiao, Weihua; Kenttämaa, Hilkka I.; Abu‐Omar, Mahdi M.; and Mosier, Nathan S. Maleic Acid and Aluminum Chloride Catalyzed Conversion of Glucose to 5‐(Hydroxymethyl) furfural and Levulinic Acid in Aqueous Media. Green Chemistry, (2016). [10.1039/C6GC01395C]Work was performed at Purdue University

Selectivity

180 oC

Fructose to HMFFructose to Humins

HMF 𝐭𝐭𝐭𝐭 𝐋𝐋𝐋𝐋HMF to Humins

AlCl3+HCl 2.6 1.0

AlCl3+MA 11 1.8

Proposed MA-Al-glucose complex ring-opening reaction

13C-NMR MA-glucose ring-opening reaction

Aldehyde signal from chain form glucose

Mass Balance comparison

Maleic Acid and Aluminum Chloride Catalyzed Conversion of Glucose to 5-(Hydroxymethyl) furfural and Levulinic Acid in Aqueous Media

Mukarakate, C., Mittal, A., Ciesielski, P.N., Budhi, S., Thompson, L., Iisa, K., Nimlos, M.R., and Donohoe, B.S. (2016). The influence of crystal allomorph and crystallinity on the products and behavior of cellulose during fast pyrolysis. ACS Sustainable Chem. Eng. DOI: 10.1021/acssuschemeng.6b00812. Work was performed at NREL

Research Details‐ Cellulose allomorphs (I, II, ,III) of varying

crystallinity generated from cotton linters.‐ Cellulose fast pyrolysis with extensive

MBMS, GCMS, TGA, XRD, and microscopic analysis of products and remaining char.

Cellulose crystal allomorph and crystallinity in fast pyrolysis

Scientific AchievementDemonstrated that crystal allomorph and relative crystallinity of cellulose can impact the products produced by fast pyrolysis.

Significance and Impact‐ relationship between cellulose crystal

forms and their high temperature properties suggests a control point to tune the slate of pyrolysis products.

‐ treatments known to alter the crystal structure of cellulose may be able to direct the slate of pyrolysis products to more desirable set of intermediates.

‐ gaining control over the cellulose synthase complex to change cellulose properties could help overcome remaining barriers for deployment of biomass fast pyrolysis.

Thermo gravimetric analysis CI‐H, CII‐H, and CIII at all crystallinity levels exhibited the highest mass loss and the highest onset of mass loss temperature.

Identification of the phenol functionality in lignin degradation products via tandem mass spectrometry based on ion-molecule reactions

Scientific AchievementTandem mass spectrometry (MS2) based on reactionsof deprotonated analytes with diethylmethoxyborane(DEMB) allows the identification of the phenol functionality in lignin degradation products while they are eluting from HPLC.

DEMBSignificance and Impact‐ Traditionally used collision-activated dissociation (CAD)

cannot be used to distinguish many isomeric lignin degradation products

‐ Certain deprotonated isomeric compounds with both phenol and carboxylic acid, aldehyde, carboxylic acidester or nitro functionalities can be differentiated via these reactions.

Zhu, Hanyu; Joann Max, Christopher Marcum, Hao Luo, Mahdi M. Abu‐Omar and Hilkka Kenttämaa. Identification of the Phenol Functionality in Deprotonated Monomeric and Dimeric Lignin Degradation Products via Tandem Mass Spectro‐metry Based on Ion‐molecule Reactions with Diethylmethoxyborane, J. Am. Soc. Mass Spectrom., 27, 1813‐1823. [10.1007/s13361‐016‐1442‐9]Work performed at Purdue University

Research Details‐ Either a stable DEMB adduct or an adduct that has

lost a methanol molecule (DEMB adduct-MeOH) isformed for deprotonated phenols

‐ Deprotonated phenols with an adjacent phenol or hydroxymethyl functionality or a conjugatedcarboxylic acid functionality can be identified basedon the formation of DEMB adduct-MeOH.

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Figure 1. (A) (top) Total ion current HPLC chromatogramfor a mixture obtained via catalytic conversion of miscanthus biomass. (bottom) Selected ion HPLC chromatogram for all ions that form a DEMB adduct. (B) Structures of the four major phenols that were identified in the mixture. (C) MS2 spectrum measured after isolation of ion 4 (m/z 165) and reaction with DEMB for 200 ms.

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