APPLICATIONS OF TECHNOLOGY:
- Biofuel production (diesel alternative)
- Flavors and fragrances
- Uses less expensive glucose as a substrate instead of fatty acids or triglycerides
- A sustainable diesel fuel alternative
- Products (methyl ketones) are nontoxic to fermentation host and released into fermentation broth
Harry Beller, Ee-Been Goh, and fellow researchers at the Joint BioEnergy Institute (JBEI) have developed a bacterial strain that can overproduce medium-chain (such as C11 to C15) methyl ketones from glucose. The methyl ketones could be blended with diesel fuel to yield a viable transportation fuel derived, in part, from renewable resources. Methyl ketones, such as 2-undecanone and 2-tridecanone, are also used in the flavor and aroma industries.
JBEI’s engineered E. coli strain overproduces ß-ketoacyl-CoAs and overexpresses a native thioesterase (FadM) not used before in metabolic engineering, to increase the methyl ketone titer of E. coli more than 4,000-fold relative to a fatty acid-overproducing strain. The technology enables the strain to overproduce a suite of methyl ketones including 2-undecanone, 2-tridecanone, and 2-pentadecanone.
For 2-undecanone, the cetane number (CN), a measure of diesel fuel performance, was determined to be 56.6, whereas the CN for a 50/50 mixture of 2-undecanone and 2-tridecanone was 58.4. These values compare favorably to commercially available diesel, which has a CN range of approximately 42 – 45.
Current production methods in the flavor and fragrance industry use fungi (such as Penicillium roqueforti) to produce methyl ketones from fatty acids or triacylglycerides (e.g., in coconut oil). Compared to solid-state fermentation using fungi, the JBEI technology can attain better productivity and relies on less expensive feedstocks (glucose).
The Joint BioEnergy Institute (JBEI, www.jbei.org) is a scientific partnership led by the Lawrence Berkeley National Laboratory and including the Sandia National Laboratories, the University of California campuses of Berkeley and Davis, the Carnegie Institution for Science and the Lawrence Livermore National Laboratory. JBEI’s primary scientific mission is to advance the development of the next generation of biofuels.
DEVELOPMENT STAGE: Bench-scale testing. The titer is ~0.5 g/l (~70% maximum theoretical yield) in 72 hours; strain improvement is ongoing.
STATUS: Patent pending. Available for licensing or collaborative research.
FOR MORE INFORMATION:
Goh, E.-B., Baidoo, E.E.K., Keasling, J.D., Beller, H.R. “Engineering of Bacterial Methyl Ketone Synthesis for Biofuels,”Applied and Environmental Microbiology 78:70-80, 2012.
Yarris, Lynn. “A Fragrant New Biofuel,” Berkeley Lab News Center, March 13, 2012.
REFERENCE NUMBER: EIB-3063