LS9 Breeds E. Coli Microbe to Produce Diesel Fuel
The E. coli directly secretes the resulting biodiesel, which then floats to the top of a fermentation vat, so there is neither the necessity for distillation or other purification processes nor the need, as in biodiesel from algae, to break the cell to get the oil out. _ScientificAmericanLS9 is one of several companies racing to engineer fuel-producing microbes that can compete with fossil fuels -- eventually putting the oil companies out of the fuel business altogether. The January 28 issue of Nature details the impressive progress of LS9 scientists in creating a breed of E. Coli capable of secreting diesel fuel from biomass.
"We incorporated genes that enabled production of biodiesel—esters [organic compounds] of fatty acids and ethanol—directly," Keasling explains. "The fuel that is produced by our E. coli can be used directly as biodiesel. In contrast, fats or oils from plants must be chemically esterified before they can be used."
Perhaps more importantly, the researchers have also imported genes that allow E. coli to secrete enzymes that break down the tough material that makes up the bulk of plants—cellulose, specifically hemicellulose—and produce the sugar needed to fuel this process. "The organism can produce the fuel from a very inexpensive sugar supply, namely cellulosic biomass," Keasling adds.
The E. coli directly secretes the resulting biodiesel, which then floats to the top of a fermentation vat, so there is neither the necessity for distillation or other purification processes nor the need, as in biodiesel from algae, to break the cell to get the oil out.
This new process for transforming E. coli into a cellulosic biodiesel refinery involves the tools of synthetic biology. For example, Keasling and his team cloned genes from Clostridium stercorarium and Bacteroides ovatus—bacteria that thrive in soil and the guts of plant-eating animals, respectively—which produce enzymes that break down cellulose. The team then added an extra bit of genetic code in the form of short amino acid sequences that instruct the altered E. coli cells to secrete the bacterial enzyme, which breaks down the plant cellulose, turning it into sugar; the E. coli in turn transforms that sugar into biodiesel.
The process is perfect for making hydrocarbons with at least 12 carbon atoms in them, ranging from diesel to chemical precursors—and even jet fuel, or kerosene. But it cannot, yet, make shorter chain hydrocarbons like gasoline. "Gasoline tends to contain short-chain hydrocarbons, say C8, with more branches, whereas diesel and jet fuel contain long-chain hydrocarbons with few branches," Keasling notes. "There are other ways to make gasoline. We are working on these technologies, as well." _SciAm
LS9 may be slightly ahead of some of the competitors in producing a fuel directly from biomass, which separates itself from the microbe and aqueous solution without the need for a costly separation step. It seems likely -- given the success of analogous pharmacological microbiological production schemes -- that LS9 will be able to scale up production to commercial scales well within the expected 10 year interval.
Such early successes should put a great deal of pressure on big money projects being supported by Exxon, Shell, BP, Chevron, Bill Gates, Vinod Khosla, Dow, DuPont, and a score of other financers of biomass to energy projects.
The cruel, greedy dictators of the petro states may well consider selling as much oil as they can while there is still a demand for the dirty old fossil variety.
Labels: microbial energy