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

BER Research Highlights

Engineered Switchgrass Shows Increased Ethanol Production During 2-Year Field Trial
Published: April 21, 2014
Posted: August 06, 2014

A major assumption in much plant-focused bioenergy research is that key plant cell wall traits can be genetically manipulated to reduce recalcitrance and increase biofuel yields per unit of biomass. A number of greenhouse experiments have shown promise, but few field studies have been completed to assess this assumption. Researchers at the BioEnergy Science Center (BESC) are the first to report a field study evaluating the biofuel potential of genetically engineered switchgrass (Panicum virgatum L.). BESC researchers previously had used RNAi (inhibitory RNA) to down-regulate caffeic acid O-methyltransferase (COMT), a key enzyme in the synthesis of lignin precursors. Switchgrass plants engineered in this way and grown in the greenhouse had less lignin and a shift in the quality of lignin to a more hydrolysable form. These plants showed less recalcitrance and a greater percentage of cell wall sugars being converted to ethanol than control plants. However, greenhouse results do not always replicate in the field, so researchers were anxious to learn if COMT-engineered switchgrass would show reduced recalcitrance and increased ethanol production when grown in the field.      

The 2-year field trial in large part recapitulated the greenhouse results. Namely, the transgenic switchgrass plants had a reduction in the quantity of lignin and a shift in the quality of lignin. A greater percentage of the cell wall sugars were released with pretreatment, and ethanol yield increased by as much as 28% in the transgenic lines relative to controls. These results were with senescent tissues, whereas the greenhouse studies had only looked at green tissues. Importantly for agronomic applications, the transgenic plants were not more susceptible to rust (Puccinia emaculata) or other plant pests. This important 2-year field study affirms genetic engineering of the plant cell wall as a viable strategy to improve plant biomass for the production of high-energy biofuels.  

Reference: Baxter, H. L.; M. Mazarei; N. Labbe; L. M. Kline; Q. Cheng; M. T. Windham; D. G. J. Mann; C. Fu; A.  Ziebell; R. W. Sykes; M. Rodriguez, Jr.; M. F. Davis; J. R. Mielenz; R. A. Dixon; Z. W. Wang; and C. N. Stewart, Jr. 2014. “Two-Year Field Analysis of Reduced Recalcitrance Transgenic Switchgrass,” Plant Biotechnology Journal 1–11. DOI:10.1111/pbi.12195. (Reference link)

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

  • 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

May 10, 2019
Quantifying Decision Uncertainty in Water Management via a Coupled Agent-Based Model
Considering risk perception can improve the representation of human decision-making processes in age [more...]

May 09, 2019
Projecting Global Urban Area Growth Through 2100 Based on Historical Time Series Data and Future Scenarios
Study provides country-specific urban area growth models and the first dataset on country-level urba [more...]

May 05, 2019
Calibrating Building Energy Demand Models to Refine Long-Term Energy Planning
A new, flexible calibration approach improved model accuracy in capturing year-to-year changes in bu [more...]

May 03, 2019
Calibration and Uncertainty Analysis of Demeter for Better Downscaling of Global Land Use and Land Cover Projections
Researchers improved the Demeter model’s performance by calibrating key parameters and establi [more...]

Apr 22, 2019
Representation of U.S. Warm Temperature Extremes in Global Climate Model Ensembles
Representation of warm temperature events varies considerably among global climate models, which has [more...]

List all highlights (possible long download time)