1. FRACTIONATION OF LIGNOCELLULOSIC BIOMASS FEEDSTOCKS
Lisette Tenlep and Douglas Raynie
Chemistry & Biochemistry
South Dakota State University

2. From ethanol to cellulosic ethanol
Ethanol is a potential fuel transportation
Biological ways to produce ethanol
Production of ethanol in the US
Corn wet mills
Corn dry mills
US Department Of Energy goals:
Make biobased ethanol practical and cost competitive by
Replace 30% of gasoline by 2030
Development of feedstocks to biofuel industry

3. Potential lignocellulosic biomass resources
Crop residues
Warm-season
Grasses
Cool-season
Other crops
Corn stover
Switchgrass
Intermediate
Wheatgrass
Forage sorghum
Soybean
Big bluestern
Red canarygrass
Sweet sorghum
Wheat straw
Indiangrass
Smooth bromegrass
Pearl millet
Rye straw
Little bluestern
Timothy
Sudangrass
Barley straw
Prairiecord grass

4. Understanding plant cell walls
Components of cell walls
Cellulose
Hemicellulose
Lignin
Other
Extractives
Resins, fats, fatty acids, salts, minerals…

5. Bioethanol production process diagram
Simplified fermentation reaction equation for glucose
C6H12O6
2 CH3CH2OH + 2 CO2
Glucose
Ethanol
Carbon dioxide

6. Pretreatment methods Physical methods Physicochemical methods
Chipping, milling, grinding
Physicochemical methods
Steam pretreatment, liquid hot-water pretreatment, ammonia fiber explosion (AFEX)…
Biological methods
Lignin-degrading microbes are applied to the lignocellulose materials.
Chemicals methods
Alkaline pretreatment, dilute acid pretreatment, organic or aqueous-organic solvent mixture

7. Organosolv processes background
Organic or aqueous-organic solvent mixture
Inorganic acid catalyst (H2SO4 or HCl)
Used to break the internal lignin and hemicellulose bonds
Dissolution of the hydrolyzed lignin
Lignin is recovered in the organophilic phase
Solubilization of most of the hemicellulose
Hemicellulose is recovered in the aqueous phase
Cellulose is retained in the biomass residue

8. Organosolv process parameters
Temperature: 140ºC
Static time: 56 minutes
Pressure: 1000 psi
Weight ratio of liquor to biomass is 10:1
Two liquor mixtures
MIBK/EtOH/H2O: 44/32/24
MIBK/EtOH/H2O: 16/34/50
H2SO4 conc: 0.025–0.1M
Solvent bottles
Extraction cell
Collection bottle
Dionex Accelerated Solvent Extraction system
Process modeled after the NREL clean fractionation procedure

9. Expected results Phase separation of the insoluble MIBK component
Addition of water to the liquor in a ratio of 1.3 parts water to 1 part liquor
Two layers
Organic phase (lignin)
Aqueous phase (hemicellulose)
Biomass residue (cellulose and extractives)

10. Lignin precipitated Lignin isolated after clean fractionation
Organic phase
Organic phase
Aqueous phase
Aqueous phase
Lignin precipitated
Lignin isolated after clean fractionation

11. Lignin distribution after fractionation

12. Hemicellulose distribution after fractionation

13. Biomass residue distribution after fractionation

14. LC characterization of sugars, byproducts and degradation products
Column type
Aminex HPX-87P
Aminex HPX-87H
Flow rate
0.6 ml/min
Temperature
85°C
65°C
Mobile phase
Bidistilled H2O
0.005 N H2SO4
Detector RI
Run time
26 minutes

15. Organophilic phase (Lignin)
Prairiecord grass
MIBK/EtOH/H2O : 44/32/24, [H2SO4 ]= 0.1M
Aminex HPX-87 H column

16. Aqueous phase (Hemicellulose)
Switchgrass
MIBK/EtOH/H2O : 44/32/24, [H2SO4 ]= 0.1M
Aminex HPX-87 H column

17. Aqueous phase cont’d (Hemicellulose)
Switchgrass
MIBK/EtOH/H2O : 44/32/24, [H2SO4 ]= 0.1M
Aminex HPX-87 H column

18. Carbohydrates distribution (MIBK/EtOH/H2O:44/32/24)
PCG SG
Carbohy
drates
0.025M H2SO4
0.05M H2SO4
0.1M H2SO4
DP4+
1.093
3.061
13.268
1.051
2.796
20.588
Cellobiose
Below dl
0.155
0.2155
0.103
0.268
Glucose
0.619
0.745
0.3685
0.344
0.365
0.8515
Xylose
1.006
1.6265
0.758
2.0335
Arabinose

19. Carbohydrates distribution (MIBK/EtOH/H2O:16/34/50)
PCG SG
Carbohydrates
0.1M H2SO4
DP4+
3.827
3.715
Cellobiose
0.071
Glucose
0.551
0.158
Xylose
0.794
0.7875
Arabinose

20. Arabinose distribution in organophilic phases

21. Future work Optimization of the pretreatment
Investigation of more liquor mixtures
Study the components distribution after these various pretreatments
Compositional analysis of all pretreated biomass residues
Determination of the amount of carbohydrates present in biomass residues
Enzymatic sacharification of preatreated biomass residues
Breakdown of cellulose into glucose

22. Acknowledgments North Central Regional Sungrant
Via funding from DOE, DOT, Verasun, ICM
2010 Center for Bioprocessing Research and Development (CBRD) at SDSU and SDSM&T
Chemistry and Biochemistry
Biology and Microbiology
Agricultural and Biosystems Engineering