Bioenergybutanol Agenda l l Bioethanol versus biodiesel Butanol

Bioenergy-butanol

Agenda l l Bioethanol versus biodiesel Butanol (CH 3 CH 2 CH 2 OH) » Chemical properties » How to make it?

Butanol

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

History l 1916 utilization of Clostridia acetobutylicum for acetone production by Chime Wizemann (fermentation process) » Smokeless gun powder l l 1945 the second most important commercial fermentation process 1960 growth of petroleum industry » Butanol production via petrochemical pathway l 1980 -2008 » Biological pathway

Ethanol versus butanol l l 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 l l High viscosity » 2 x ethanol » 5 -10 x gasoline » Problems in the fuel systems of butanol-fueled cars Lower octane number compared to ethanol » Lower compression ratio and efficiency

Butanol-properties l l l Sweet smelling solvent Industrial solvent High melting point of 25. 5°C causes it to gel and freeze near room temperature » Additive in gasoline l Industrial commodity » 370 million gallon/year » $3. 75/gallon » Petrochemical route

Production of butanol (1) l 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) l ABE fermentation (butanol, acetone, ethanol) butanol: acetone: ethanol (6: 3: 1) » Other by-products: – – l 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) l Ethanol » S. cerevisiae (yeast) » Temp 30°C » p. H 6 » No extracellular enzymes » Monomeric sugars (6 C) » Products: 50% ethanol, 50% CO 2 » Toxicity of the final product over 100 g/L of ethanol l Butanol » Clostridium (bacteria) » Temp 30 -40°C » p. H 6. 8 -7 drops to 5. 0 (acidogenesis) and increases to 7. 0 (solventogenesis) » Presence of extracellular enzymes » Starch, cellobiose and monomers (5 and 6 C) » Variety of products » Toxicity of the final products – 20 g/L max of acetone, butanol, and ethanol

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

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

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