![Page 1: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/1.jpg)
Alkaline pretreatment of wheat straw
“Analytical methods for non-wood raw materials and their products and processes”
COST FP0901 meeting, 19-21 August 2010, Hamburg
Richard Gosselink, Hans van der Kolk, Paulien Harmsen, Robert Bakker
![Page 2: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/2.jpg)
Outline presentation
� Wheat straw biorefinery
� Alkaline pretreatment
� Analytical tools
� Highlights results
� Available samples for Round Robin COST PF0901
2
![Page 3: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/3.jpg)
Wheat straw biorefinery concept
Clark et al. 2006
S L
3
![Page 4: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/4.jpg)
Pretreatment
� Goal� Fractionation of lignocellulosic to cellulose, hemicellulose and
lignin � Make cellulose and hemicellulose fractions more accessible for
enzymatic hydrolysis� Make lignin available for higher-valued products
� Numerous processes � Mechanical, chemical, enzymatic� Acids, alkaline, organic solvents � Combinations thereof
4
![Page 5: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/5.jpg)
Alkaline pretreatment (high pH)
� Alkali induces swelling of biomass, leading to increase of internal surface area
� Disruption of lignin structure (lignin removal)� Reduction of cellulose crystallinity
� Results in improved accessibility of cellulose and hemicellulose towards enzymatic hydrolysis
5
![Page 6: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/6.jpg)
Alkaline pretreatment
� Common alkaline pretreatment route� Base as catalyst (NaOH, Ca(OH)2, ammonia); T<120 °C� Carried out under (close to) atmospheric conditions� Long reaction times (hours)� Need for chemical recycling
� Improve alkaline pretreatment� Apply milder process conditions
• Less formation of degradation products (e.g. inhibitors)• Lower operational costs
� Improve accessibility of sugars to enzymes� Obtain lignin of high purity
6
![Page 7: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/7.jpg)
From wheat straw to fermentable sugars
Wheat straw
PretreatmentEnzymatic hydrolysis
Fermentation
Lignin
Ethanol or
ABE
Polymeric sugars
Monomeric sugars
� Pretreatment efficiency� Properties of solid fraction (cellulose-rich)
• Biochemical composition
� Properties of liquid fraction
• Sugars, organic acids and lignins in solution
• Recovery of lignin
� Enzymatic hydrolysis� Conversion of solid fraction
• Glucan to glucose• Xylan to xylose
� Standard procedure
• 50 °C, 120h
• Excess of enzyme (GC220)
7
![Page 8: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/8.jpg)
Experimental setup
Base case: 4h alkaline pretreatment in stirred reactor
� Preliminary experiments (2 L, 70 °C)� Base case� Effect NaOH-concentration
� Main experiments (200 L, 90 °C)� Base case � Extrusion� Refining
8
![Page 9: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/9.jpg)
Analytical tools (selection)� Biochemical composition untreated & pretreated straw (solids)
� Extraction (ASE)
� Carbohydrates (HPAEC-PAD)
� Lignin (AIL by weight, ASL by UV)� Ash (TGA, ignition)
� Proteins (N by Kjehldahl or Dumas, AA by UPLC)
� Morphology (SEM)
� Cellulose cristallinity (WAXS)� Liquids
� Carbohydrates (monomers, oligomers)
� Lignin� Fermentation inhibitors (phenolics, organic acids by LC)
� Isolated lignin
� FT-IR � Impurities (carbohydrates, proteins, ash)
� MWD (alkaline SEC)1
� Functional groups (31P NMR)1
0.0 10.0 20.0 30.0 40.0 50.0-100
0
100
200
300
400
500 RG070918 #27 [modified by User, 5 peaks manually assigned] ECD_1nC
min
1 - fucose - 5.2172 - Rhamnose - 12.0003 - Arabinose - 12.800
4 - Galactose - 17.033
5 - Glucose - 19.733
6 - Xylose - 24.0507 - Mannose - 25.6508 - 32.6839 - 34.033
SampleName: Organosolv lignin ARD 1 SampleName: Organosolv lignin ARD 2
3934
- 2
0.1
21
AU
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
Minutes
0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00 24.00 26.00 28.00 30.00 32.00 34.00
AliphaticOH Internal std SyringylOH
GuaiacylOH
p-CoumarylOH
COOH
Cond. Arom.OH
1Gosselink, R.J.A. et al. Holzforschung 20109
![Page 10: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/10.jpg)
Pretreatment efficiency Solid fraction
33 36 3844 41
2224 26
3027
20
23 18
1417
0
20
40
60
80
100
Wheatstraw
0% NaOH 6% NaOH 9% NaOH 12% NaOH
Bio
chem
ical
co
mp
osi
tio
n (
wt%
)Other
Ash (TGA)
Lignin
Hemicelluloses
Cellulose
NaOH-conc as wt% dry biomass
10
![Page 11: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/11.jpg)
Pretreatment efficiency Liquid fraction
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,40
7009001100130015001700
Wavenumber (cm-1)
Ab
sorb
ance
Wheat straw lignin reference
0% NaOH
6% NaOH
9% NaOH
12% NaOHAromatic skeleton lignin
CO stretching carbohydrates
IR-spectra of lignins isolated from liquid fraction
11
![Page 12: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/12.jpg)
Enzymatic hydrolysis Solid fraction
� Enhanced enzymatic degradability due to pretreatment� Structural changes of wheat straw (e.g. delignification)� Minimal formation of degradation products due to mild conditions
0
20
40
60
80
100
Wheatstraw
0 wt%NaOH
6 wt%NaOH
9 wt%NaOH
12 wt%NaOH
Pol
ysac
char
ide
conv
ersi
on (w
t%)
Glucose
Xylose
12
![Page 13: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/13.jpg)
� Pretreatment� Main action is delignification (max 50%)� Minimum degree of hemicellulose and cellulose hydrolysis� Solid fraction enriched with sugars due to pretreatment (from 60% to 75%)� Optimal NaOH concentration 9 wt%
� Lignin � Low purity
� Enzymatic hydrolysis� Conversion of glucan and xylan improved from < 20% to > 80%
� Input for further experiments� Increase T from 70 to 90 °C� NaOH concentration 6-9 wt% NaOH
Summary Base case (2L)
13
![Page 14: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/14.jpg)
Experimental setup
Base case: 4h alkaline pretreatment in stirred reactor
� Preliminary experiments (2 L, 70 °C)� Base case
� Main experiments (200 L, 90 °C)� Base case � Extrusion� Refining
14
![Page 15: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/15.jpg)
Base case
� Chopped wheat straw (1-2 cm)� 9 wt% NaOH based on dry straw� 4h at 90 °C
15
![Page 16: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/16.jpg)
Extrusion
1st DelignificationWhole wheat straw
6 wt% NaOH, 2h, 90°C
2nd Delignification6 wt% NaOH, 2h, 90 °C
� Transport of biomass to RSE (reversed screw element) � Accumulation and compression of material� High compression and shear forces� Material is dry and absorbs added chemicals very well (e.g. NaOH)
� Shortening of fibres and fibrillation
Steam
RSE
Chemicals
FilterSteam
RSE
Chemicals
FilterSteamSteam
RSERSE
Chemicals
Filter
16
![Page 17: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/17.jpg)
Refining
1st DelignificationChopped wheat straw
6 wt% NaOH, 2h, 90 °C
2nd Delignification6 wt% NaOH, 2h, 90°C
� Shear and compression forces� Increase of surface area� Shortening of fibres and fibrillation� Homogeneous, clean fibres
17
![Page 18: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/18.jpg)
Scanning Electron Microscopy
Refining
100 µm
Extrusion
100 µm
Base case
100 µm
Wheat straw
100 µm
18
![Page 19: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/19.jpg)
Pretreatment efficiency Solid fraction
33
4551 52
22
2726 2620
1211 9
0
20
40
60
80
100
Wheat straw Base case Extrusion Refining
Bio
hem
ical
co
mp
osi
tio
n (
wt%
)
Other
Ash (TGA)
Lignin
Hemicelluloses
Cellulose
19
![Page 20: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/20.jpg)
Pretreatment efficiency Liquid fraction
� Direct analysis of sugar monomers
� After acid hydrolysis, 3h, 100°C
� Substantial increase of sugars
� Liquid fraction� Sugars mainly present as
oligomers (total 6%)
Total sugar release
0%
1%
2%
3%
4%
5%
6%
0 1 2 3 4
Time (h)
Su
gar
s (w
t% d
ry s
traw
)
Alkaline: Oligomers and monomers
0.0
0.5
1.0
1.5
2.0
2.5
Rhamnose Arabinose Galactose Glucose Xylose Mannose
Co
nce
ntr
atio
n (
g/l)
Alk-1-L1
Alk-1-L2
Alk-1-L3
Alk-1-L4
Alkaline: Monomers
0.000
0.005
0.010
0.015
0.020
0.025
Rhamnose Arabinose Galactose Glucose Xylose Mannose
Co
nce
ntr
atio
n (
g/l)
Alk-1-L1
Alk-1-L2
Alk-1-L3
Alk-1-L4
20
Amounts 100x lower
![Page 21: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/21.jpg)
Pretreatment efficiency Liquid fraction
� Liquid fraction� Acetic acid primary fermentation inhibitor� Lactic acid present� Phenolic compounds present at very low levels
Mel
kzuu
r -
8.56
8
Azi
jnzu
ur -
10.
118
26.6
19
AU
-0.002
0.000
0.002
0.004
0.006
0.008
0.010
0.012
0.014
0.016
0.018
0.020
0.022
Minutes2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00 24.00 26.00 28.00 30.00 32.00 34.00 36.00 38.00
AU
0 .00
0.01
0.02
0.03
0.04
Minutes
2 .00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00 24.00 26.00 28.00 30.00 32.00
Sy
rin
gic
Ac
id -
3.1
78
Sy
rin
ga
lde
hy
de
- 5
.96
7
Co
um
ari
c A
cid
- 7
.15
6
Fe
rulic
Ac
id -
10
.35
5
tra
ns
-Cin
na
mic
Ac
id I
S -
25
.82
0
21
![Page 22: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/22.jpg)
Pretreatment efficiency Liquid fraction
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,40
6508501050125014501650
Wavenumber (cm-1)
Ab
sorb
ance
Wheat straw lignin Base caseExtrusionRefining
Aromatic skeleton lignin
CO stretching carbohydrates
IR-spectra of lignins isolated from liquid fraction
22
![Page 23: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/23.jpg)
Lignin: Chemical composition
� Formation of lignin carbohydrate complexes (LCC)?
1 2 1 2 110 7
13 13 18
75 8075 73 68
0
20
40
60
80
100
Ligninbase case
Ligninbase case(conical)
LigninExtrusion
(B)
Ligninrefining(atm P)
Ligninrefining(elev P)
Bio
chem
ical
co
mp
osi
tio
n (
wt%
)
Other
Ash (TGA)
Lignin
Hemicelluloses
Cellulose
23
![Page 24: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/24.jpg)
Lignin: MWD by alkaline SEC
321918810PD
28000170001800053008100Mw (Da)
8909001000690700Mn (Da)
Refining (elevP)
Refining (atmP)
ExtrusionBase case
Reference lignin1Parameter
� Depending on pretreatment method different lignins obtained
� Biomass more accessible due to mechanical pretreatment: less degradation of lignins?
1Soda wheat straw lignin supplied by Granit SA24
![Page 25: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/25.jpg)
Lignin: Functional groups by 31P NMR
31P NMR analysis performed by VTT
IS = Endo-N-Hydroxy-5-norbornene-
2,3-dicarboximide
Amounts of different hydroxyl group species (mmol/g) in lignin Sample ID Aliphatic
OH Aromatic
OH S+C G H Carboxylic
acid Total OH
Base case 3,72 1,14 0,30 0,62 0,22 0,89 5,75 Refining (atmP) 4,00 0,49 0,03 0,37 0,09 0,57 5,05 Refining (elevP) 3,97 0,85 0,24 0,48 0,14 0,68 5,50 S + C = Syringyl + Condensed phenolic units, G = Guaiacyl phenolic units and H = p-Hydroxyphenyl phenolic units
25
![Page 26: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/26.jpg)
Pretreatment efficiency
20-30%20-30%<10%Sugars in liquid fraction
70-80%70-80%40-50%Delignification
60-65%60-65%70-75%Yield solid fraction
RefiningExtrusionBase case
� Extrusion and refining comparable results� Higher degree of delignification accompanied by loss of
sugars by hydrolysis
26
![Page 27: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/27.jpg)
Enzymatic hydrolysis Solid fraction
0
20
40
60
80
100
Wheat straw Base case Extrusion Refining
Po
lysa
cch
arid
e co
nve
rsio
n (
wt%
)
Glucose
Xylose
27
![Page 28: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/28.jpg)
Conclusions
� Alkaline pretreatment excellent for� Delignification (40-50%)� Improvement of enzymatic degradability (from 20 to 70-80%)
� Added value extrusion or refining� More delignification (70-80%)� Further improvement of enzymatic degradability (from 20 to 100%)
� Different lignins produced� Moderate purity (80%)� Molar mass relatively high
� Economic feasibility of combined mechanical/alkaline pretreatment depends on value of lignin produced
� Analytical tools suitable for process development
28
![Page 29: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/29.jpg)
Available samples for Round Robin
� Wheat straw (kg)
� Base case: Alkaline pretreated wheat straw (kg)� Neutralised + washed + stored @ -20°C
� Black liquor stored @ -20°C (kg)
� Isolated soda wheat straw lignin (100-200g, expectedearly September)
29
![Page 30: Alkaline pretreatment of wheat strawweb.abo.fi/.../11_Hamburg_presentation_Gosselink.pdf · 2010-09-16 · Outline presentation Wheat straw biorefinery Alkaline pretreatment Analytical](https://reader034.vdocuments.net/reader034/viewer/2022042805/5f6610611491cb57ec2c3348/html5/thumbnails/30.jpg)
Acknowledgements
� Biosynergy www.biosynergy.eu
� Biobutanol www.biobutanol.nl
30
www.biosynergy.eu