BER launches Environmental System Science Program. Visit our new website under construction!

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

BER Research Highlights

Microbial Conversion of Switchgrass to Multiple Drop-In Biofuels
Published: November 28, 2011
Posted: January 12, 2012

The low efficiency and high cost of enzymes used to break down plant material into sugars remains a major barrier to economically competitive production of cellulosic biofuels. Consolidated biomass processing, in which a single microorganism both produces cellulose-degrading enzymes and converts the resulting sugars to a desired biofuel, presents a promising alternative to improve efficiency and reduce costs, but few organisms naturally possess both capabilities. Researchers at the Joint Bioenergy Institute (JBEI) have now engineeered a modified strain of the workhorse industrial microbe E. coli that expresses a tailored set of cellulases, allowing it to degrade both the cellulose and hemicellulose chains released from switchgrass pretreated with ionic liquid. This was accomplished by cloning cellulase genes from Cellvibrio japonicus, a soil microbe with similar protein secretion systems to E. coli, and modifying the genes to allow proper timing and level of cellulase expression in the host. The team then added metabolic pathways that allowed E. coli to convert resulting sugars to either of two drop-in automotive biofuels (biodiesel and butanol) or a jet fuel precursor terpene compound. This presents a promising new advance in consolidated biomass processing, and, given the relative ease of genetic modification in E. coli, offers tremendous potential for subsequent engineering to increase conversion efficiency or synthesize a broader range of fuels.

Reference: Bokinsky, G., P. P. Peralta-Yahyn, A. George, B. M. Holmes, E. J. Steen, J. Dietrich, T. S. Lee, D. Tullman-Ercek, C. A. Voigt, B. A. Simmons, and J. D. Keasling. 2011. "Synthesis of Three Advanced Biofuels from Ionic Liquid-Pretreated Switchgrass Using Engineered Escherichia coli," Proceedings of the National Academy of Sciences of the United States 108(50), 19949-54. DOI: 10.1073/pnas.1106958108. (Reference link)

Contact: Joseph Graber, SC-23.2, (301) 903-1239
Topic Areas:

  • Research Area: Microbes and Communities
  • Research Area: Plant Systems and Feedstocks, Plant-Microbe Interactions
  • Research Area: Sustainable Biofuels and Bioproducts
  • Research Area: DOE Bioenergy Research Centers (BRC)
  • Research Area: Biosystems Design

Division: SC-33.2 Biological Systems Science Division, BER


BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

Mar 23, 2021
Molecular Connections from Plants to Fungi to Ants
Lipids transfer energy and serve as an inter-kingdom communication tool in leaf-cutter ants&rsqu [more...]

Mar 19, 2021
Microbes Use Ancient Metabolism to Cycle Phosphorus
Microbial cycling of phosphorus through reduction-oxidation reactions is older and more widespre [more...]

Feb 22, 2021
Warming Soil Means Stronger Microbe Networks
Soil warming leads to more complex, larger, and more connected networks of microbes in those soi [more...]

Jan 27, 2021
Labeling the Thale Cress Metabolites
New data pipeline identifies metabolites following heavy isotope labeling.

Analysis [more...]

Aug 31, 2020
Novel Bacterial Clade Reveals Origin of Form I Rubisco

  • All plant biomass is sourced from the carbon-fixing enzyme Rub [more...]

List all highlights (possible long download time)