Using Bacteria To Make Diesel from Biomass  

Technology Review has an article on LS9's second generation biofuel production process using engineered E. coli bacteria - Bacteria Make Diesel from Biomass.

Engineered bacteria have been rewired with the genetic machinery necessary to convert cellulose into a range of chemicals, including diesel fuel. The bacteria, developed by South San Francisco company LS9 in collaboration with researchers at the University of California, Berkeley, make the necessary enzymes for every step along the synthesis pathway and can convert biomass into fuel without the need for additional processing. LS9 has demonstrated the bacteria in pilot-scale reactors and plans to scale the process to a commercial level later this year.

Jay Keasling, professor of chemical engineering and bioengineering at UC Berkeley and one of LS9's founders, and scientists at LS9 report engineering E. coli bacteria to synthesize and excrete the enzyme hemicellulase, which breaks down cellulose into sugars. The bacteria can then convert those sugars into a variety of chemicals--diesel fuel among them. The final products are excreted by the bacteria and then float to the top of the fermentation vat before being siphoned off.

Using these methods, it's possible to create a range of fuels from biomass, but LS9 is focusing on diesel rather than fuels similar to gasoline for the time being, says Stephen del Cardayre, the company's vice president of research and development. Diesel specifications are easier to meet and the market for diesel is growing by 2 to 4 percent a year, while that for gasoline is flat. Last May, LS9 partnered with Procter & Gamble to develop fuels as well as commodity chemicals.