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Scale-up of Ionic Liquid Pretreatment and Enzymatic Hydrolysis of
Lignocellulosic Biomass for Biofuels Production Chenlin Li1, Deepti Tanjore1, Wei He1, Jessica Wong1, James L. Gardner1, Rakesh R. Banka1, Kenneth Sale2, Seema Singh2, Blake A. Simmons2
1Advanced Biofuels Process Demonstration Unit, Lawrence Berkeley National Laboratory, Emeryville, CA; 2Joint BioEnergy Institute, Emeryville, CA
Polymer Poster Symposium GLBRC Retreat, Chicago, IL, March 21-23, 2012
Milling
Switchgrass
Scale Up Ionic liquid Pretreatment and Saccharification
Recovery of pretreated solids
10L Parr reactor
10-15%
Biomass in
[C2mim][OAc]
Washing of solids
10%
Biomass
loading
Saccharification
Grinding
Precipitation
Pretreatment and Saccharification Equipment at ABPDU
10L Parr Reactors 2L Hydrolysis Reactors
Basket Centrifuge 50L Hydrolysis Reactors
Analytical Equipment at ABPDU
HPAEC Gas Chromatography
Rheology Bomb Calorimery
Acknowledgements
Small Scale Ionic Liquid Pretreatment Process
Heat
Stir
Solubilized biomass
Heat
Time
Anti
solvent
Mix
Biomass
Filter
Dry
Recovered product
3% Biomass in
[C2mim][OAc]
Summary and Ongoing Work
Summary:
• Successfully scaled up the IL pretreatment of switchgrass to 6L scale and 15%
loading
• Achieved consistent cellulose recovery and hemicellulose/lignin removal
• Successfully scaled up the enzymatic saccharification of IL pretreated
switchgrass to 2L scale and 10% loading with fast and high sugar recovery
Ongoing Work
• Enzymatic cocktail optimization for high solid loading biomass saccharification
• Scale up of IL pretreatment and saccharification of various feedstocks at high
solid loading
• Develop process mass balance and energy balance
Viscous Nature of Pretreated Switchgrass
0
10
20
30
40
50
60
70
80
90
1.00E+00
1.00E+01
1.00E+02
1.00E+03
1.00E+04
0 50 100 150 200 250
Ph
ase
An
gle
Vis
coel
ast
ic p
rop
erti
es (
Pa
)
Varying Shear Stress (Pa) at Constant Frequency (1 Hz)
Shear modulus (complex component)(Pa) Shear modulus (complex component)(Pa)
Phase angle(°) Phase angle(°)
After Pretreatment After Washing
Changes of Switchgrass Compositions
0
10
20
30
40
50
60
70
80
Glucose Xylose Lignin Glucose Xylose Lignin
Co
mp
osi
tio
n (
%)
Untreated
10 mL scale (3% w/w solid loading)
6 L scale (15% w/w solid loading)
160 C 120 C
0
5
10
15
20
25
30
35
40
45
50
5 8 12 24 48 72
Su
gar
rele
ase
d (
g/L
)
Time (h)
Arabinose Xylose
Glucose Cellobiose
Enzymatic Saccharification of IL Pretreated Switchgrass
Biomass loading: 10% (w/w)
Enzyme loading: 54 mg Ctec2 /g glucan
6 mg Htec2/g glucan
88% of enzymatic glucose recovery
and 40% of xylose recovery at 48h
on the basis of pretreated solids
Addition of HTec2 increased
xylose release by 35%
Enzyme cocktails optimization
targeting at high solid loading in
progress
Residual Ionic Liquid Caused Inhibition to Hydrolysis
Solutions:
0
10
20
30
40
50
60
0
20
40
60
80
100
120
1 2 3 4 5
IL c
on
cen
trati
on
in
rec
ov
ered
bio
ma
ss (
%w
/w)
Su
ga
r yie
ld i
n h
yd
roly
sis
liq
uo
r b
ase
d o
n
un
trea
ted
co
mp
osi
tio
n (
%)
Solids recovered after given number of washes
Arabinose Glucose
Xylose IL Content
Extensive washing steps
IL/hydrolysates separation
IL tolerant enzyme development
IL tolerant microorganisms
Mass Balance of IL Pretreated Switchgrass
33.3%
3.7%
16.2%
15.6%
5.2%
16.8%
9.2%
160ºC 120ºC
Abstract
To access the sugars in lignocellulosic biomass, pretreatment is an essential step to
deconstruct the recalcitrant plant cell wall structures and facilitate enzymatic hydrolysis of
recovered cellulose. Ionic liquid (IL) pretreatment is gaining substantial attention as a potential
pretreatment process that can efficiently fractionate biomass and provide clean sugar substrate
for the production of ethanol and other advanced biofuels. Previous work at Joint BioEnergy
Institute (JBEI) has demonstrated at milliliter scales that IL can dissolve significant amounts of
several feedstocks and produce highly digestible polysaccharides. However, a key factor in the
development of economically viable lignocellulosic biofuels is to establish novel pretreatment
technologies coupled with saccharification by advanced enzyme systems at process relevant
scales.
Building on the milliliter scale optimization, JBEI, in collaboration with Advanced
Biofuels Process Demonstration Unit (ABPDU) is taking the first step to demonstrate IL
pretreatment and subsequent saccharification at high solid loadings, liter scales (6 L) with
variety of feedstocks. The scaling effects, mixing, washing, IL inhibition, and process energy
flow are under evaluation and optimization to achieve a robust and reproducible technology
based on the state-of-the-art facilities available at ABPDU. The knowledge gained from these
initial scale-up studies will be critical and essential in developing techno-economic models for
ionic liquid pretreatment and saccharification at larger scales, primarily in demonstrating
commercial viability of this promising technology.
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