Understanding and Enhancing Alkaline and Oxidative Chemical Pretreatments for the Oxidative Chemical Pretreatments for the Production of Biofuels through Improved Characterization Characterization Da vid Hodge Assistant Professor Chemical Engineering, Michigan State University 3 rd International Symposium on Bioenergy and Biotechnology Wuhan, Hubei, P.R. China 16 October, 2012
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Understanding and Enhancing Alkaline and Oxidative Chemical Pretreatments for theOxidative Chemical Pretreatments for the Production of Biofuels through Improved
CharacterizationCharacterization
David Hodgea d odgeAssistant Professor
Chemical Engineering, Michigan State Universityg g, g y
3rd International Symposium on y pBioenergy and Biotechnology
Wuhan, Hubei, P.R. China
16 October, 2012
Plant Tissues are Diverse and Highly HeterogeneousStorage Tissues: Food Crops Structural Tissues: Plant Cell Walls
Starch Granules in Corn Endosperm Source: USDA/ARS/ERRC
Alkaline Hydrogen Peroxide PretreatmentBased on existing alkaline hydrogenBased on existing alkaline hydrogen peroxide pulp bleaching stages in the paper industry
Alkaline‐oxidative pretreatments as either standalone pretreatments ORdelignifying “finishing” post‐delignifying finishing postpretreatment step
Unique advantagesWell‐suited for grasses
Current Challenges:
Alkaline hydrogen peroxide bleaching tower >1000 tpd capacity at Smurfit‐K K f li Pi å S d ( h
Process integration
Economics
Water use/recycleKappa Kraftliner, Piteå, Sweden (photo courtesy: Outokumpu Oy)
/ y
Alkaline Hydrogen Peroxide PretreatmentBased on existing alkaline hydrogenBased on existing alkaline hydrogen peroxide pulp bleaching stages in the paper industry
Current Challenges: Bioenergy Grasses:• Switchgrass
Process integration
Economics
Water use/recycle
g• Miscanthus sp. • Reed Canary Grass
/ y
Alkaline Hydrogen Peroxide PretreatmentBased on existing alkaline hydrogenBased on existing alkaline hydrogen peroxide pulp bleaching stages in the paper industry
Alkaline‐oxidative pretreatments as either standalone pretreatments ORdelignifying “finishing” post‐
A hSolids transferred to Solids transferred to the
50%
60%
70%
80%
onen
t Fraction
Ash
Water+EtOH Extractives
Acetate
Uronic Acids
Galactan50%
60%
70%
80%
onen
t Fraction
Ash
Water+EtOH Extractives
Acetate
Uronic Acids
GalactanInsoluble Insoluble
Solids transferred to the liquid phase
Solids transferred to the liquid phase (hydrolysate)
10%
20%
30%
40%
Compo
Galactan
Mannan
Arabinan
Xylan
Glucan10%
20%
30%
40%
Compo
Galactan
Mannan
Arabinan
Xylan
Glucan
FractionFraction
0%
0 3 6 12 18 30 36 42 48
Pretreatment Time (h)
Lignin (Klason)
ASL
0%
0 3 6 12 18 30 36 42 48
Pretreatment Time (h)
Lignin (Klason)
ASL0 4 8 12 16 20 24 28 32 36 40 44 48
Hydrolysis Time (h)Banerjee et al. (2012). BiotechnolBioeng. 109(4):922‐931.
Pretreatment, 0 hPretreatment, 0 hIntegration of AHP Pretreatment,
Hydrolysis, and Fermentation
on o
f ne
nts
y y ,
70
80
90
Glc Xly
Y87 (pH5.5) OD 1
6
8
Pretreatment, 48 hPretreatment, 48 h
solu
biliz
atio
all c
ompo
n
30
40
50
60
conc
. (g/
l)
y EtOH Xylitol glycerol OD 600
4
OD
600
Xylose-fermenting Saccharomyces
Hydrolysis, 0 Hydrolysis, 0 hrhr
crea
sing
san
t cel
l wa
0 50 100 150 200 2500
10
20
0
2
Inc
pla
1.67 g/L YNB w/o ammonium sulfate and 2 27 g/L of urea
0 50 100 150 200 250
time (h)
Hydrolysis, 24 Hydrolysis, 24 hrhrand 2.27 g/L of urea
Filter Sterilize
Fermentation
Sterilize(0.22 μm)
Liu et al. (in preparation).
Relating Cell Wall Properties to RecalcitranceUnderstanding cell wall properties impacting recalcitrance and relationship of these properties to enzymatic digestibility
Using pretreatment of plant cell walls with diverse phenotypes to t l ith di l it tigenerate samples with diverse recalcitrance properties
Analytical ToolProperty Impacting Recalcitrance
Water adsorption/retention
Potentiometric titration
Cell wall hydrophilicity
Cellulose oxidation
Glycome Profiling
Klason Lignin
Polysaccharide accessibility
Lignin content
HPLC
Pyrolysis‐GC/MS
Ferulate content
S/G ratio
Thioacidolysis‐GC/MS
HSQC NMR
Lignin condensation
Diverse Cell Wall Properties: BiomassMonocot grasses
Corn Stovers (Zea mays)• Pioneer hybrid 36H56
• Inbred brown midrib bm1Inbred brown midrib bm1
• Inbred brown midrib bm3
Switchgrass(Panicum virgatum cv. Cave‐in‐Rock)
Miscanthus (Miscanthus x giganteus )
Woody dicotHybrid poplar
(Populus nigra var Charkoviensis x Caudina)
Herbaceous dicot
(Populus nigra var. Charkoviensis x Caudina)
Goldenrod (Solidago sp.)dicot
Diverse Cell Wall Properties: Pretreatments 15
AHP
Soda pulping
Liquid Hot Water + qAHP post‐treatment
Cu(bpy)‐catalyzed AHP t t tAHP pretreatment
Cell Wall – Water Interactions ObjectivesHow can cell wall–water interactions Property: Cell impact deconstruction
High‐throughput destructive characterization of complete cell wallsBased on characterization of volatilized pyrolysis productspy y pPyrolysis for 10 s at 600oC, heated transfer line to GC/MS at 300oC
Correlating Digestibility to Plant Cell Wall Properties
Solubilized ferulate is correlated to glucan digestibility
Pyrolytic 4‐vinylguaiacolPyrolytic 4 vinylguaiacol (Ferulate/Lignin): Correlated to lignin content and glucandigestibilitydigestibility
800000
28
G monomer S monomerDetermine relative quantities of (0.38)(0.26)(0.99)(0.86)(S/G)
Lignin Methods: Thioacidolysis GC/MS
500000
600000
700000Determine relative quantities of G, S, H lignins
Foster et al., 2010. J Vis Exps, 37
bm1bm3
0 6
0.7
0.8
0.9
1.0
Mon
omers Re
leased
lysis
p‐Hydroxyphenyl (H)
Guiacyl (G)
Syringyl (S)
( )( )( )( )( )
100000
200000
300000
400000
Cleavage of alkyl‐aryl ethers in ligninQuantification of derivatized 0.2
0.3
0.4
0.5
0.6
ive Fraction
of Lignin M
by Thioacido
08.05 8.15 8.25 8.35 8.45 8.55 8.65 8.75
fragments by GC‐MSProblematic in grasses?
• Highly condensed ligninsGC MS
Time (minutes)
0.0
0.1
Pioneer Hybrid Stover
bm1 Inbred Stover
bm3 Inbred Stover
Switchgrass (cv. Cave‐In‐Rock)
Relati
GC-MS quantification
BSTF
CPG-SM
EtSH, BF3
β-O-4 linkageLi et al. (2012). BiotechnolBiofuels. 5(1)38.
29Quantitative ThioacidolysisDetermines the fraction of lignin involved in only ether linkagesDetermines the fraction of lignin involved in only ether linkagesThioacidolysis yield decreased from 5‐12% w/w to 1% w/w after pretreatment
AHP pretreatment solubilizing 50% lignin
Fraction of condensed lignin increased from 88‐95% w/w to 99% w/wLi et al. (2012). BiotechnolBiofuels. 5(1)38.
No AHP, no xylanaseAHP, no xylanaseAHP, xylanaseAHPwith Cu(bpy) no xylanase
Catalyst significantly improves subsequent enzymatic conversion of cellulose
60%
version
AHP with Cu(bpy), no xylanaseCu(bpy) AHP, xylanase
40%
Glucan Co
nv
20%
0%24 48 72
Hydrolysis time (h)Li et al. (accepted 2012). Biotechnol Bioeng.
Oxidative Depolymerization of CelluloseO R
COOHOH
R HO
AHP depolymerizes cellulose (filter paper)
OO
COOHOHHO
C6 oxidation
?(filter paper)
Introduces ‐COOHO
OO
R
OHOH
OHOH
RHO
HO
Cellulose
O
HO
R
OH
OH
HO
on+
O
OHRHO
?
?
OOH
OH
R HO
COOH
C1 oxid
ation+OH OH
O R
OH
OH
HO
OC4 oxidation
+?
Li et al. (accepted 2012). Biotechnol Bioeng.
www.glbrc.org
SummaryW t d ti d t ti b l t d
32
Water adsorption and retention can be correlated to enzymatic conversion
Correlating digestibility to plant cell wall propertiesNegative relationship between Klason lignin and di ibili di ll lldigestibility across diverse cell wall typesFerulate content quantified by Py‐GC/MS in residual cell wall and LC/MS in hydrolysates can be correlated towall and LC/MS in hydrolysates can be correlated to lignin removal and digestibility
Oxidative cellulose depolymerization and –COOH p yintroduction demonstratedImpact on digestibility improvement?
AcknowledgementsResearch Group:
Dan WilliamsMarc Hansen(†) Ryan Stoklosa
Dr. Tongjun LiuCharles Chen
Collaborators:Eric Hegg, MSUChris Saffron MSU
David Hodge Muyang LiAlex Smith(†)y
Zhenglun LiChris Saffron, MSUJonathan Walton, MSUMichael Hahn, U. GeorgiaTrey Sato U WisconsinTrey Sato, U. WisconsinArt Ragauskas, Georgia
Funding:DOE, BER DE‐FC02‐07ER64494,DOT, NE Sun Grant InitiativeNSF, DUE #0757020
Not pictured: pElizabeth Häggbjer, Natassa Christides, Genevieve Gagnier