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

BER Research Highlights


Eucalyptus Trees with Reduced Lignin Content Display Reduced Recalcitrance
Published: August 27, 2015
Posted: September 25, 2015

Lignocellulosic materials offer an attractive replacement for food-based crops used to produce ethanol, but understanding the interactions within the cell wall is vital to overcome the highly recalcitrant nature of lignocellulosic biomass. One factor imparting plant cell wall recalcitrance is lignin, which can be manipulated by making changes in the lignin biosynthetic pathway. Changes to lignin gene expression in switchgrass and Populus have shown increased sugar release and reduced recalcitrance. Researchers at the Department of Energy’s BioEnergy Science Center have sought to transfer these results to eucalyptus, a fast-growing, warm climate, woody biofeedstock also suitable for cellulosic biofuel production. The researchers genetically engineered reduced gene expression of two key lignin biosynthesis enzymes, cinnamate 4-hydroxylase (C4H) and p-coumaroyl quinate/shikimate 3'-hydroxylase (C3'H), in eucalyptus. The engineered plants were evaluated for cell wall composition and reduced recalcitrance. Eucalyptus trees with down-regulated C4H or C3'H expression displayed lowered overall lignin content than the control samples. The C3'H and C4H down-regulated lines also had different lignin compositions when compared to the control eucalyptus trees. Both the C4H and C3'H down-regulated lines had reduced recalcitrance as indicated by increased sugar release, which was determined using enzymatic conversion assays utilizing both no pretreatment and a hot water pretreatment. Lowering lignin content rather than altering lignin content was found to have the largest impact on reducing recalcitrance of the transgenic eucalyptus variants. The development of lower recalcitrance trees opens up the possibility of using alternative pretreatment strategies in biomass conversion processes that can reduce processing costs.

Reference: Sykes, R. W., E. L. Gjersing, K. Foutz, W. H. Rottmann, S. A. Kuhn, C. E. Foster, A. Ziebell, G. B. Turner, S. R. Decker, M. A. W. Hinchee, and M. F. Davis. 2015. “Down Regulation of P-Coumaroyl Quinate/Shikimate 3'-Hydroxylase (C3'H) and Cinnamate 4-Hydroxylase (C4H) Genes in the Lignin Biosynthetic Pathway of Eucalyptus urophylla x E. grandis Leads to Improved Sugar Release,” Biotechnology for Biofuels 8,128. DOI: 10.1186/s13068-015-0316-x. (Reference link)

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

  • Research Area: Genomic Analysis and Systems Biology
  • 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)