1. Apollo Program for Biomass Liquids What Will it Take?
Michael R. Ladisch
Laboratory of Renewable Resources Engineering
Agricultural and Biological Engineering
Purdue University

2. Corn
Source: Nicolle Rager Fuller, National Science Foundation

3. Supply Chain Grow Harvest Store Transport Sun Water Seed Fertilizer
to Bioprocessing

4. Build on Existing Infrastructure for Corn
Trucking the feedstock
Trips of 5 to 40 miles, one way, for corn
Costs about
12 cents per bushel corn
4.6 cents per gallon ethanol
$ 5 / ton (dry basis) corn
10 cents per cu. ft. corn
Maier and Ileleji, 2006

5. Corn Weighs more than Corn Stover (Cellulose) translates to larger storage volumes for cellulose feedstock for a given ethanol production
Corn
Corn Stover (Cellulose)

6. Supply Chains: Store, then Transport
Sun
Water
Grow
Harvest
Seed
Fertilizer
Transport
Store
to Bioprocessing

7. Bioprocessing Pretreatment Hydrolysis Fermentation Fuel Ethanol
Enzymes
Yeast
Glucose xylose
Pretreatment
Hydrolysis
Fermentation
Fuel Ethanol
Distillation
Delivery to markets Infrastructure

8. Projections: US Ethanol Production
(corn)
(corn + cellulose)
(corn + more cellulose)
(a lot of cellulose + corn)
It will happen here

9. Ethanol Plant Locations

10. Biomass Resources in Tons / sq km /year
Sets stage for Cellulose Ethanol
From NREL Website, 2005

11. Corn Stover: 1 to 2 tons /acre
Leaves
Cobs
Stalks
Corn… Corn Stover are the parts of the corn plant as shown, These parts are high cellulose, hemicelluloses and lignin. Both the cellulose and hemicelluloses have the potential to yield sugars that can be fermented to ethanol.
Roots

12. Bioethanol Production
Feedstock
Preparation
Pretreatment
Bio is…….As an intriguing substitute, sustainable bioethanol shows great market potentials. However, Bioethanol’s high cost makes it uncompetitive to petroleumCorn stover preferred (ready supply in Midwest)
Hot water pretreatment
-hydrates cellulose structure
-minimize degradation productes
Major steps in biomass-to-bioethanol process
The major steps in biomass-to-ethanol process are feedstock preparation (cleaning and size reduction), pretreatment, enzymatic hydrolysis and ethanologenic fermentation. Developments in all aspect will all contributed to reduce the cost of bioethanol. Hot water pretreatment
cost-effective
maximize the solubilization of the hemicellulose fraction1,2
minimize the formation of sugar monomers1,2
Liquid hot water pretreatment has several advantages: 1) only water no other chemicals. 2) An optimized hot water pretreatment would maximize the solubilization of the hemicellulose fraction as liquid soluble oligosaccharides while the formation of sugar monomers is minimized. It prevents the degradation of the monomeric sugars to harmful degradation products.
Corn stover as a promising lignocellulose food stock for ethanol production has continued to receive a great deal of attention because it is available in bulk quantities at relatively low cost.
Ethanol-from biomass production is seen as a high-potential technology that offers great benefits to the market and the environment. By replacing gasoline with ethanol as transportation fuel, urban air pollution and global warming may be ameliorated, the US economy will then become less dependent on foreign oil, and jobs will be created in the agriculture sector. Lignocellulosic biomass feedstocks typically contain 55%--75% by dry weight carbohydrates that are polymers of five- and six-carbon sugar units which can be converted to ethanol by SSF. Corn stover is one of the cereal lignocellulose, which makes up a large portion of the agricultural residues.
2.SSF refers to simultaneous saccharification and fermentation of the biomass. It combines the enzymatic hydrolysis of polymeric cellulose to monosaccharides with the fermentative conversion of these monomers to ethanol in the same environment.
3. Although rich in carbohydrates, biomass is an insoluble substrate with complex structure: cellulose fibers are embedded in a sheath of hemicellulose and lignin, and held together by hydrogen and van der waals bonds. The structure makes lignocellulose recalcitrant to enzymatic break down.
4. So a pretreatment step is required to increase the digestibility of cellulose before it is exposed to enzymes. Basically, as shown, in the pretreatment, the compact relations between different components will be destroyed, makes it relax and amenable to enzymatic conversion. There are several ways for pretreatment : mechanical, physical or chemical pretreatment. Hot water pretreatment was firstly introduced by our lab and was approved to be comparable to other chemical methods in efficiency and more economical.
Hydrolysis of Solids
Ethanol
Fermentation

13. Pretreatment gives enzyme accessible substrate
Cellulose
Lignin
Pretreatment
Hemicellulose
Amorphous Region
Crystalline Region
Pretreatment changes the physical structure of the cellulose portion (black lines) as well as disrupting the lignin (a glue like material) that protects the cellulose from hydrolysis (pink line). The structure – once disrupted by pretreatment is opened up and is amenable to hydrolysis since the catalysts that cause hydrolysis to occur can get into the cellulose structure.

14. Components of plant cell walls
Cellulose
Cellulose
Fermentable sugars obtained from cellulose in 1819
Lignin
Lignin
Hemicellulose
(need special yeast to convert to ethanol)
Extractives
Extractives
Ash
Ash
Chapple, 2006; Ladisch, 1979

15. Yeast Metabolism: pentose fermentation
Xylose
Glucose
NAD(P)H
NAD(P)+
Xylitol
Glucose-6-P
NAD+
NADH
Fructose-6-P
Xylulose
Glyceraldehyde-3-P
Xylulose-5-P
NAD+
NADH
3-Phosphoglycerate
PPP
Ethanol
NADH
NAD+
Phosphoenolpyruvate
Ho et al
TCA Cycle
Pyruvate
Acetaldehyde

16. Yields of Ethanol from Corn Stover (Cellulose Ethanol)
From Cellulose: 50 to 55 gal / ton
From Xylan: to 35 gal / ton
Total: 80 to 85 gal / ton.
Corresponds to about 250,000 tons /yr for 20 million gal per year plant
Requires engineered yeast, pretreatment cellulase enzymes

17. Other molecules from biomass sugars
Fermentable sugars are the feedstock
Products in addition to ethanol
Butanol, Acetone
2,3 Butanediol
Acetic, Lactic acid
Microbial polysaccahrides (for enhanced oil recovery)
Ladisch et al, 1979; 1991

18. *Supported by the NSF Plant Genome Research and REU Programs
Plant Cell Wall Genomics at Purdue
Identified over 1100 genes involved in cell wall construction
Generated over 900 mutants in Arabidopsis and 200 in maize; maize mutants represent a resource of genetic diversity for feedstock testing
Characterized cell walls of these materials using spectroscopic, chemical, and imaging assays
Identified novel cell-wall genes that can contribute to feedstock diversity
Used genetics and molecular biology to analyze the functions of cell-wall gene products
This slide summarizes the scope of work accomplished by our cell wall genomics team. This multi-institutional team received a grant from the National Science Foundation’s Plant Genome Research Program ($6M) to characterize cell-wall mutants of maize and Arabidopsis using high-throughput screening by infrared spectroscopy. Maize and Arabidopsis are representative of the two distinct kinds of growing walls made by flowering plants.
*Supported by the NSF Plant Genome Research and REU Programs

19. Trees: 5 to 10 tons /acre Chapple and Meilan, 2006

20. Switchgrass: 5 to 10 tons /acre, less inputs
Elbersen, Wageningen, 2004

21. Using Hay 1 Bale = 970 lbs = 2000 miles Assuming 50 gal x 40 mpg
Engel, 2006

22. Vision
Learning and engagement to illustrate science and engineering as agents of change
Transfer discovery from laboratory to the field or plant in a contiguous high tech / biotech / agriculture corridor
Combine engineering, science and agriculture to catalyze of sustainable growth of a US bioenergy sector
Work is not complete until it proven valuable to industry.

23. Challenges: What will it take?
Utilize biomass materials from a wide range of sources:
Cellulosics
Fiber
Corn
Apply biotechnology and nanotechnology to
develop bio-catalytic conversion routes
Yeasts
Fixed bed catalysts
Enzymes

24. Opportunities Designer crops for bio-energy production
Bioprocess Engineering built around advanced biocatalysts (yeasts, enzymes, fixed bed catalysts) that process designer crops
High energy corn that maximizes polysaccharides rather than oil or protein
Understand role of forages (switchgrass) and wood poplar grown for energy crops
Seeds for the same

25. Research Plant genomics Microbial genomics Bioprocess Engineering
Agriculture
Economics
Industrial Test Beds

26. Bioprocess Discovery Activities
advanced pretreatments integrated with plant science
to enhance the digestibility/reactivity of the fiber component
(cellulose and hemicellulose) of DG,
enzymatic hydrolysis of pretreated celluloses
to produce fermentable sugars, remove part or all of the cellulose and hemicellulose, increase feed value of residual solids,
ferment hexose and pentoses using genetically engineered yeasts
to ethanol and their transformation to other biobased products,
Bio-catalysts to make diesel from soybeans, sugars from biomass
convert alcohol and soybean oil to diesel
Separations technology
energy efficient recovery form water of different bio-products
6. comprehensive economic analysis
of the processes, technologies, and markets, incorporating uncertainty in key technological and market parameters.

27. Concluding Thoughts
“Increasing energy consumption, coupled with decreased petroleum supplies, has made development of alternate energy sources a pressing national problem.
“Changes in technology and philosophy will be required in order to establish a renewable resource base for the …industry.
“Utilizing cellulosics as this basis, we are tapping the earth’s most abundant and readily renewable resource, while providing our industry with relatively inexpensive, and reliable, raw materials.
Quote from 1979.