Metabolic Engineering of Clostridium Tyrobutyricum for Butanol Production

A new strain of bacteria that can produce butanol at a high titer for transportation fuel.

The Need

Butanol is generally used as an industrial solvent but can also be blended with gasoline and used as transportation fuel. Butanol is commonly produced using fossil fuels, but it can also be produced from biomass, referred to as biobutanol. Biobutanol is produced from fermentation of the same feedstocks as ethanol - corn, sugar beets, and other types of biomass. (Alternative Fuels Data Center, U.S. Dept. of Energy). Traditionally, biobutanol was fermented in a process that produced acetone and ethanol along with the butanol. This process is known as ABE and used microbes that were poisoned by the butanol it produced once the alcohol reached a certain concentration. In addition, the yield was low and highly susceptible to butanol toxicity. New methods of producing large amounts of clean butanol are needed to further adaptation of this solvent for transportation fuels.

The Technology

Researchers at The Ohio State University led by Drs. Shang-Tian Yang and Mingrui Yu have produced a novel strain of Clostridium that has a high acid tolerance, allowing the production of butanol as the sole solvent product. The fermentation process with this novel butanol-producing bacterium can double the butanol yield and concentration, thus reducing the product cost to an economically competitive level for both chemical and fuel applications.

Commercial Applications

  • Industrial solvents
    • Lacquers and enamels
  • Biofuels

Benefits/ Advantages

  • Higher butanol yield and high titer
  • Less susceptible to butanol toxicity
  • The bacteria has a high acid and butanol tolerance
  • New strains are less sensitive to environmental factors and demonstrate robustness and consistency

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