1. Bioenergy-butanol

2. Agenda Bioethanol versus biodiesel Butanol (CH3CH2CH2CH2OH)
Chemical properties
How to make it?

3. Butanol

4. Feedstock Any starch/sugar rich biomass Agricultural biomass
Corn
Wheat
Sugar cane
Sugar beets
Straws
Corn stover
Woody biomass

5. History
1916 utilization of Clostridia acetobutylicum for acetone production by Chime Wizemann (fermentation process)
Smokeless gun powder
1945 the second most important commercial fermentation process
1960 growth of petroleum industry
Butanol production via petrochemical pathway
Biological pathway

6. Ethanol versus butanol
Energy efficiency
Butanol 96% of gasoline
Less volatile than ethanol
Less corrosive than ethanol
Water-tolerant alternate fuel
Less hydroscopic than ethanol (it doesn't pick up water)
pipeline
High viscosity
2x ethanol
5-10x gasoline
Problems in the fuel systems of butanol-fueled cars
Lower octane number compared to ethanol
Lower compression ratio and efficiency

7. Butanol-properties Sweet smelling solvent Industrial solvent
High melting point of 25.5°C causes it to gel and freeze near room temperature
Additive in gasoline
Industrial commodity
370million gallon/year
$3.75/gallon
Petrochemical route

8. Production of butanol (1)
Fermentation
Weizmann organism (chemist Weizmann)
Anaerobic bacteria
Starch, sugars
Extracellular amylolytic enzymes
 and  amylase
Glucoamylase etc.
Distillation (boiling point)
Clostridium acetobutylicum, the "Weizmann Organism"

9. ABE fermentation (2)
ABE fermentation (butanol, acetone, ethanol) butanol:acetone:ethanol (6:3:1)
Other by-products:
Acetic acid
Lactic acid
Propionic acids
Isopropanol
1 bushel of corn:
1.3 gallons of butanol
0.65 gallons of acetone
0.22 gallons of ethanol (each 1-2%)

10. Ethanol versus butanol fermentation (1)
S. cerevisiae (yeast)
Temp 30°C
pH 6
No extracellular enzymes
Monomeric sugars (6C)
Products: 50% ethanol, 50% CO2
Toxicity of the final product over 100g/L of ethanol
Butanol
Clostridium (bacteria)
Temp 30-40°C
pH drops to 5.0 (acidogenesis) and increases to 7.0 (solventogenesis)
Presence of extracellular enzymes
Starch, cellobiose and monomers (5 and 6C)
Variety of products
Toxicity of the final products
20g/L max of acetone, butanol, and ethanol

11. Ethanol versus butanol fermentation (2)
Ethanol S. cerevisiae
Butanol Clostridium

12. ABE fermentation (3) Pure sugar source Lignocellulosic substrate
Toxicity of butanol to C.acetobutylicum
ethanol, thus butanol, higher recovery cost of butanol
Lignocellulosic substrate
More inhibitors generated during pretreatment
Lower butanol yields

13. Cars running on butanol
Over 10,000 miles around and across US