U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights


Enhancing Microbial Pathways for Biofuel Production
Published: October 17, 2014
Posted: March 12, 2015

Produced in microbes and plants, terpenes are high-energy compounds that could be used for producing biofuels. For example, U.S. Department of Energy (DOE) researchers at the Joint BioEnergy Institute (JBEI) had reported that bisabolane, a biofuel derived from the sesquiterpene precursor bisabolene, could serve as an alternative to diesel fuel. Enhancing terpene yields in suitable microbes and plants is thus an important step toward commercial-scale production of these biofuels. Terpene synthesis in the majority of bacterial species, as well as in plant plastids, takes place via a pathway in which one-sixth of the carbon in the starting metabolites is lost as carbon dioxide (CO2). JBEI researchers wanted to improve terpene production in Escherichia coli by developing a pathway that would not result in any carbon loss as CO2. To do this, they focused on using a novel route that would form terpenes from 5-carbon (C5) sugars such as xylose, which is a breakdown product of hemicellulose. The researchers created a mutant in the metabolism of C5 sugars and then selected for complementary mutants that could grow on the C5 sugar xylose. E. coli colonies that were able to grow under this selective pressure were sequenced at DOE’s Joint Genome Institute and all were found to have mutations in the ribB gene. The researchers then inserted the pathway for bisabolene production into the strains able to grow on xylose, and they found bisabolene production in these strains. Further manipulation of the pathways by gene fusion and varying the gene order enhanced bisabolene yields several fold. These results demonstrate that biosynthetic pathways that are not found in nature may be constructed by selection and targeted engineering. This pathway is can now be further optimized for terpene yield in preparation for commercial-scale production.

Reference: Kirby, J., M. Nishimoto, R. W. N. Chow, E. E. K. Baidoo, G. Wang, J. Martin, W. Schackwitz, R. Chan, J. L. Fortman, and J. D. Keasling. 2015. “Enhancing Terpene Yield from Sugars via Novel Routes to 1-Deoxy-d-Xylulose 5-Phosphate,” Applied and Environmental Microbiology 81,130–8. DOI: 10.1128/AEM.02920-14. (Reference link)

Contact: Kent Peters, SC-23.2, (301) 903-5549
Topic Areas:

  • Research Area: Genomic Analysis and Systems Biology
  • Research Area: Microbes and Communities
  • Research Area: Plant Systems and Feedstocks, Plant-Microbe Interactions
  • Research Area: DOE Joint Genome Institute (JGI)
  • Research Area: Sustainable Biofuels and Bioproducts
  • Research Area: DOE Bioenergy Research Centers (BRC)

Division: SC-23.2 Biological Systems Science Division, BER

 

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