1 - Bio-butanol production: scope, significance, and applications

Abstract

Butanol is a colorless flammable four-carbon alcohol with a characteristic banana-like odor that is currently used as an industrial solvent in the manufacturing of plasticizers, butylamines, butyl acetate, butyl acrylate and methacrylate, glycol ethers and amino resins. In addition, butanol has some properties that make it a viable transportation fuel. These properties include a low flash point, hydrophilicity, vapor pressure and volatility, large energy content per unit mass, and miscibility with hydrocarbon-based fuels. Some of these properties make butanol less corrosive and compatible with the existing oil infrastructure. As interest in environmentally compatible fuels intensifies, butanol is one of the chemicals that have gained attention of scientists and engineers as a potential replacement for gasoline. Meanwhile, butanol fermentation, popularly known as acetone-butanol-ethanol (ABE) fermentation, has a rich history that dates to Louis Pasteur, who in 1861 observed that bacteria can produce butanol. The ABE fermentation is plagued with less-than-optimal butanol titers in the bioreactor due to the inhibitory effect of butanol on fermenting microorganisms. The cost of butanol recovery from the fermentation broth, however, is the second largest contributor to the production cost, the first being the substrate cost. Development of knowledge-based strategies to resolve complex issues related to substrate compatibility and butanol toxicity to butanol-producing microorganisms is evolving. Consequently, in this chapter, there is elaboration on the scope of butanol-producing microorganisms, butanol production from food- and nonfood-based feedstock, technology innovations to advance butanol fermentation, and significance and applications of butanol and butanol derivatives.