Bioenergy-butanol

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

Bioethanol versus biodiesel Feedstocks (competition with food industry) Major producers Process Yields Production facilities

Butanol

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

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 1980-2008 Biological pathway

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

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

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"

ABE fermentation (2) ABE fermentation (acetone, butanol, 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%)

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 6.8-7 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

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

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

Fermentation improvements C.beijernickii Hydrolysis, fermentation and recovery of butanol in 1 reactor GM E.coli Conversion of keto acids (components of a.a biosynthetic pathway) to butanol Acetoacetic acid

Environmental Energy Inc. 2.5 gallons of butanol per corn bushel no acetone or ethanol Other processes have not been able to achieve better than 1.3 to 1.9 gallons of butanol per bushel+A+E.

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