Researching E. Coli’s Methyl Ketones: Possible Biofuel?


e.coli usesIn the last two years, the  U.S. Dept. of Energy (DOE)’s Joint BioEnergy Institute (JBEI) engineered E. Coli bacteria to convert glucose into significant quantities of methyl ketones. Methyl ketones are a class of chemical compounds. These chemical compounds are used primarily for fragrances and flavors (in cheese oddly enough) and for essential oils.

However, recent research is showing the bacteria is capable of much more. It could provide us with a clean, green, renewable blending agent needed in creation of diesel fuel.

With more genetic modifications, they have been able to boost the E.coli’s methyl ketone production 160-fold.

Methyl ketones are naturally occurring compounds discovered more over a century ago in the aromatic evergreen plant known called Rue. Methly ketones have since been discovered in tomatoes and other plants, as well as insects and microorganisms.

The researchers made two major modifications to E. coli: They modified specific steps the metabolic pathway that E. coli uses to break down fatty acids called beta-oxidation. Then they increased the expression of a native E. coli enzyme called FadM. The combination of these two modifications enhanced the production of methyl ketones. (Beller) Next they made further modifications that ultimately led to the production of 40% of the maximum theoretical yield known for methyl ketones.

Harry Beller, a JBEI microbiologist who led the study stated this, “Although the improved production is still not at a commercial level in the biofuel market, it is near a commercial level for use in flavor and fragrances, where certain methyl ketones are much more highly valued than they would be in the biofuel market,” Beller says. “It may be possible for a company to sell a small percentage of methyl ketones in the flavor and fragrance market and use the profits to enhance the economic viability of the production of methyl ketones as biofuels.”

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Lawerence Berkeley National Laboratory