Research Highlights

Cellulosic bioenergy offers environmental benefits not available from other biofuels, but requires substantial amounts of land and creates the potential for environmental harm. It is therefore important to understand how different bioenergy crop and management choices will simultaneously affect climate mitigation, biodiversity, reactive nitrogen loss, and water use in future biofuel landscapes.

To improve bioenergy crop composition and yield, we seek to understand activation of the unfolded protein response (UPR) and its impact on the ability of plant cells to accumulate easily digestible carbohydrates such as mixed-linkage glucan (MLG). Here we identify a Brachypodium UPR transcription factor, UPR genes responsive to chemical or heat stress, and impacts of heat stress on MLG accumulation.

To develop bioenergy crops that produce extra lipids for extraction as oil biofuel, we examined whether lipid transport complexes of plants with different lipid acyl composition have diverged in their function.

Bioenergy sorghum accumulates 75% of shoot biomass in its stem internodes. To identify genes and molecular mechanisms that modulate the extent of internode growth, we conducted microscopic and transcriptomic analyses of four successive sub-apical vegetative internodes representing different stages of internode development of the bioenergy sorghum genotype R.07020.

We used transposon sequencing (Tn-seq) to identify essential genes in the bacterium Rhodobacter sphaeroides under several growth conditions. We then used that data to evaluate and refine an existing genome-scale metabolic model, providing more precise systems-level understanding of the diverse metabolic lifestyles of this bacterium.

To better understand flowering time control in temperate grasses, we sought to identify which genes prevent a grass from flowering until it has undergone prolonged cold exposure. After screening for and identifying mutants in the grass species Brachypodium distachyon, we identified a mutant that flowers rapidly without cold exposure and described and characterized a new gene we named REPRESSOR OF VERNALIZATION1 (RVR1).

Microbial production of lipids in high yield presents a significant challenge, often falling short of what can be theoretically obtained. This study characterized high-lipid mutant variants of Rhodobacter sphaeroides and showed that alterations to the bacterial cell envelope can result in increased accumulation of lipids relative to the parent strain.

Researchers show that the three main components of plant biomass can be converted to high value products in economically favorable yields when using the solvent gamma-valerolactone (GVL) to break apart the biomass.

Biomass pretreatment remains an essential step in lignocellulosic biofuel production, largely to facilitate the efficient removal of lignin and increase enzyme accessibility to the polysaccharides There have been significant efforts in planta to reduce lignin content or modify its composition to overcome the inherent recalcitrance

Pretreating lignocellulosic biomass using microbes such as C. thermocellum enables a one-pot process for breaking down sugars and fermenting those sugars for fuel and chemicals. In this study, we examined the bacterium’s efficiency in breaking down cellulose in industrially relevant pretreated biomass, finding that pretreatments that remove both lignin and hemicellulose can help improve the specific activity of the bacterium’s cellulosomal enzymes.