Butanol as an industrial solvent has been in use since the early 1900's. Butanol and acetone were produced by the Acetone-Butanol-Ethanol (ABE) process using Clostridium acetobutylicum to ferment substrates such as corn and molasses.

the history of butanol

During World War 1, this anaerobic fermentation process was used primarily for producing acetone for the production of explosives. Over the years improvements were made to the process to improve yield, and to produce different mixtures of solvents. Different strains of Clostridia were used, as well as different feedstocks, and additives and nutrients were incorporated in order to improve the overall fermentation reaction. This process was operated at a commercial scale using the oxo or aldol process until the 1950's when cheap petroleum became available and petroleum became the primary source for butanol production.

the energy problem

Rising oil prices, diminishing supplies, increasing demand, environmental impact, and national security have all contributed to growing concerns about an impending energy crisis. As a result, there has been a renewed interest in sustainable fuels and innovative fuel production processes, whereby fuel extenders and fuel alternatives are seen as a way to reduce our dependence on foreign oil, while at the same time reducing emissions. Ethanol has attracted the majority of media attention in recent years as a fuel extender because it can be produced from feedstocks such as corn and will reduce emissions. Though ethanol is a good interim solution that will not entirely be displaced, butanol has physical properties that make it a better biofuel alternative. Furthermore, the fact that butanol is complementary to ethanol makes it a logical and feasible step in the path toward energy independence.

Butanol fermentation, however, has traditionally been constrained by self-limitation of the reaction due to the toxic effect of the product on the microorganism involved in the process. This limitation restricts viability of butanol and higher "bioholic" fuel bio-production. What has been missing is an efficient, continuous, butanol fermentation process competitive with current petrochemical production.