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

Engineering Escherichia coli to Tolerate Ionic Liquids for Biofuel Production
Published: March 26, 2014
Posted: August 06, 2014

Ionic liquids (IL) are a class of environmentally friendly solvents that are effective at loosening cellulose from lignin in plant biomass. This is an important step in the production of biofuels as it makes cellulose available for breakdown into its component sugars. The sugars are fermented into biofuels by microbes such as Escherichia coli. While most of the IL is recovered from the processed biomass, some remains and can inhibit the growth of E. coli and the enzymes that convert cellulose into biofuel, greatly reducing yields of biofuel product. To address this inhibition, scientists at the U.S. Department of Energy’s Joint BioEnergy Institute (JBEI) looked for genes that might confer tolerance on the E. coli to the ILs. They looked to Enterobacter lignolyticus, a bacterium known to grow in the presence of ILs. First, they moved large parts of the E. lignolyticus genome into E. coli and asked the E. coli to grow in the presence of the IL. Several colonies were found to now tolerate the IL; each colony had two E. lignolyticus genes in common, an efflux pump gene and its regulator. Efflux pumps confer tolerances by transporting toxic compounds out of the cell into the medium. To determine if the tolerance conferring efflux pump could improve biofuel synthesis in the presence of IL, the efflux pump genes were placed together in a strain of E. coli engineered to produce a biofuel precursor, bisabolene. The resulting strain was able to produce more bisabolene in the presence of much greater amounts of IL than the E. coli strain without the efflux pump. An E. coli strain that tolerates ILs and synthesizes bisabolene means that ILs can be used to treat biomass to free cellulose from lignin without negatively impacting subsequent biofuel production. This can reduce biofuel production costs because extra expense is not needed to remove the last amounts of IL from the processed biomass. As cellulosic biofuel production plants come online, such adaption of technological advances like these that will improve their economic viability.

Reference: Rüegg, T. L., E.-M. Kim, B. A. Simmons, J. D. Keasling, S. W. Singer, T. S. Lee, and M. P. Thelen. 2014. “An Auto-Inducible Mechanism for Ionic Liquid Resistance in Microbial Biofuel Production,” Nature Communications 5. DOI:10.1038/ncomms4490. (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: 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)