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

BER Research Highlights


Ionic Liquids: Degrading Biomass but Not Biofuel-Producing Microbes
Published: May 14, 2012
Posted: August 21, 2012

A major hurdle to the development of economically competitive biofuels remains the difficulty of separating long sugar chains from plant biomass (cellulose and hemicellulose) from the tough network of lignin that gives strength and resilience. Pretreatment of plant material by ionic liquids (ILs), a class of salts that are molten at room temperature, is highly effective in disrupting biomass structure and liberating cellulose chains for subsequent conversion to biofuel compounds by fermentative microbes. However, residual IL molecules are highly toxic to biofuel-producing microbes and must be fully removed from the cellulose fraction prior to conversion, an expensive and time-consuming process. To understand this IL toxicity and enable development of resistant strains of microbes, researchers at the Joint Bioenergy Institute (JBEI) examined shifts in gene expression of a novel biomass-degrading bacterium when exposed to an IL. Enterobacter lignolyticus was surprisingly resistant to IL exposure, altering its cell membrane composition, activating a series of pumps to remove IL from the cell interior, and balancing osmotic pressure across the cell membrane. Many of the response mechanisms were specific to IL exposure and were not triggered by exposure to standard salts. These findings provide new insights into the mechanisms used by microbes to tolerate exposure to ionic liquids and may lead to the improvement of IL tolerance in biofuel-producing microbes through targeted genetic engineering.

Reference: Khudyakov, J. I., P. D'haeseleer, S. E. Borglin, K. M. DeAngelis, H. Woo, E. A. Lindquist, T. C. Hazen, B. A. Simmons, and M. P. Thelen. 2012. "Global Transcriptome Response to Ionic Liquid by a Tropical Rain Forest Soil Bacterium, Enterobacter lignolyticus," Proceedings of the National Academy of Sciences of the USA 109(32), E2173-E2182. DOI: 10.1073/pnas.1112750109. (Reference link)

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

Aug 24, 2019
New Approach for Studying How Microbes Influence Their Environment
A diverse group of scientists suggests a common framework and targeting of known microbial processes [more...]

Aug 08, 2019
Nutrient-Hungry Peatland Microbes Reduce Carbon Loss Under Warmer Conditions
Enzyme production in peatlands reduces carbon lost to respiration under future high temperatures. [more...]

Aug 05, 2019
Amazon Forest Response to CO2 Fertilization Dependent on Plant Phosphorus Acquisition
AmazonFACE Model Intercomparison. The Science Plant growth is dependent on the availabi [more...]

Jul 29, 2019
A Slippery Slope: Soil Carbon Destabilization
Carbon gain or loss depends on the balance between competing biological, chemical, and physical reac [more...]

Jul 15, 2019
Field Evaluation of Gas Analyzers for Measuring Ecosystem Fluxes
How gas analyzer type and correction method impact measured fluxes. The Science A side- [more...]

List all highlights (possible long download time)