Biobutanol

Butanol may be used as a fuel in an internal combustion engine. It is more similar to gasoline than it is to ethanol. A C4-hydrocarbon, butanol is a drop-in fuel and thus works in vehicles designed for use with gasoline without modification. Both n-butanol and isobutanol have been studied as possible fuels. Both can be produced from biomass (as "biobutanol" ) as well as from fossil fuels (as "petrobutanol"). The chemical properties depend on the isomer (n-butanol or isobutanol), not on the production method. Although intriguing in many ways, butanol fuel is rarely economically competitive. Obtaining higher yields of butanol involves manipulation of the metabolic networks using metabolic engineering and genetic engineering. While significant progress has been made, fermentation pathways for producing butanol remain inefficient. Titer and yields are low and separation is very expensive. As such, microbial production of butanol is not cost-competitive relative to petroleum-derived butanol. Although unproven commercially, combining electrochemical and microbial production methods may offer a way to produce butanol from sustainable sources. Escherichia coli, or E. coli, is a Gram-negative, rod-shaped bacterium. E. coli is the microorganism most likely to move on to commercial production of isobutanol. In its engineered form, E. coli produces the highest yields of isobutanol of any microorganism. Methods such as elementary mode analysis have been used to improve the metabolic efficiency of E. coli so that larger quantities of isobutanol may be produced. E. coli is an ideal isobutanol bio-synthesizer for several reasons: E. coli is an organism for which several tools of genetic manipulation exist, and it is an organism for which an extensive body of scientific literature exists. This wealth of knowledge allows E. coli to be easily modified by scientists. E. coli has the capacity to use lignocellulose (waste plant matter left over from agriculture) in the synthesis of isobutanol. The use of lignocellulose prevents E.