Research Highlights

Optimizing how we break down biomass is critical to developing valuable chemicals from renewable materials such as plant lignin. GLBRC researchers found that the bacteria Novosphingobium aromaticivorans rapidly breaks the β-aryl ether bond commonly found in lignin, and that its enzyme, a Nu-class glutathione S-transferase, performs the critical step of removing the antioxidant glutathione.

Grass species, which are among the major renewable feedstocks supporting biofuel production, can provide an abundant source of mixed-linkage glucan (MLG), a glucose polymer. Improving biofuel crops by increasing sugar yields requires a thorough understanding of biosynthetic mechanisms. In this study, GLBRC researchers demonstrated that MLG is present in the Golgi apparatus, in post-Golgi structures, and in the cell wall; these findings provide new insight on how to modify the localization of MLG synthase to maximize production of MLG.

The copper-catalyzed alkaline hydrogen peroxide (Cu-AHP) deconstruction process is highly effective at pretreating a genetically-modified type of poplar called "zip-lignin" poplar, resulting in high sugar yields for biofuel fermentation even when inputs are reduced. Zip-lignin poplar incorporates weak linkages into lignin, the hard-to-process compound that gives plant cell walls their sturdiness, rendering the poplar especially amenable to the Cu-AHP deconstruction method.

Spatial dependence, or the likelihood that nearby land units are more likely to be related than more distant ones, has effects on landowners' willingness to make land available for bioenergy production.

In this study, we used chemical genomics (CG) to identify the mechanisms of GVL toxicity to fermentative microbes. We identified gene deletions that confer sensitivity or tolerance to the solvent and then used this knowledge to engineer a xylose-fermenting yeast strain with improved tolerance to GVL and enhanced conversion of sugars to biofuel.

Many bacteria contain enzymes with the potential to convert renewable carbon sources into substitutes for compounds derived from petroleum. For example, the β-etherase pathway present in sphingomonad bacteria could cleave the abundant β-ether bonds in plant lignin, releasing a bio-based source of aromatic compounds for the chemical industry. In this study, GLBRC researchers demonstrated biodegradation of lignin polymers using a minimal set of β-etherase pathway enzymes.

We showed that Canary Island date palm (Phoenix canariensis) lignification uses an unprecedented range of monolignol conjugates, the distribution of which varies depending on the tissue region, indicating that they may play specific roles in the cell walls in these tissues and/or in the plant’s defense system.

In this study we characterized the impacts of biofuel cropping systems on soil microbial communities, finding that these communities were strikingly different depending on soil depth.

In this study, we further characterized a mutant gene (wri1-1) in the plant Arabidopsis that leads to strong reduction in seed oil content. We also identified a primary root defect and confirmed altered homeostasis in auxin, a growth regulator that plays an important role in plant development.

In this study, we identified flowering time gene candidates that could be employed to manipulate flowering time in upland, cold-tolerant switchgrass cultivars, with the goal of increasing total biomass yield for these northern accessions.