Research Highlights

Recent advancements from the lignin biosynthetic research community provide a greater understanding of lignin composition and structure, including revelations about new, previously unknown components of the lignin polymer; this makes it possible to imagine what features an “ideal lignin” might have. In this collaborative study, GLBRC researchers and their colleagues describe the ideal nature of catechyl lignin (C-lignin) via a revised compositional characterization, advantageous features in regard to reactivity and stability, and their successful attempt to convert C-lignin polymers to monomers in near-quantitative yields.

This holistic biomass-to-wheels analysis showed that, contrary to conventional wisdom, seeking atom-economical biomass-to-fuel strategies may not necessarily be the optimal objective towards the development of the next generation biofuels. In addition to carbon yield, the study identified the energy requirements of the process and the resulting biofuel type and quality to be key factors that should be considered simultaneously in the selection of alternative biofuels and development of new biofuel strategies.

In this study, researchers examined natural diverse isolates of Saccaromyces cerevisiae for tolerance to ILs and identified two genes associated with this outcome. Analysis of specific gene variants suggests that tolerance may be governed in part by the degree to which ILs can be pumped out of cells.

Bioenergy cropping systems can act as sinks or sources of atmospheric carbon dioxide, depending on the balance between the formation and decomposition of organic carbon.

GLBRC researchers processed and experimentally quantified ethanol production from five different herbaceous feedstocks: two annuals (corn stover and energy sorghum) and three perennials (switchgrass, miscanthus, and restored prairie). They determined that a range of plant types could be used in a lignocellulosic ethanol refinery without having a major impact on field-scale ethanol yield, which represents the ethanol production per land area.

In this study, GLBRC researchers tested the hypothesis that microbial communities could be used to produce valuable compounds, such as medium-chain fatty acids (MCFAs), from lignocellulosic stillage. Techno-economic analyses showed that, at the productivity of MCFAs achieved in this study, valorizing lignocellulosic ethanol stillage to MCFAs could improve the economic sustainability of a biorefinery.

Unlike harvest of corn stover, which is linked to grain harvest, timing of harvest for energy grasses such as switchgrass is relatively flexible. In this study, GLBRC scientists aimed to determine if switchgrass harvest could be timed to maximize beneficial impacts on fermentation while avoiding production of harmful degradation compounds.

As plant breeding programs embrace the idea of the biorefinery, lignin is emerging as a potential feedstock for commodity chemicals. To improve our understanding of lignin’s chemical structure and find potential bioproducts in lignin, GLBRC researchers developed a powerful analytical method to identify new and low-abundance compounds within the complex lignin biopolymer.

Comprehensive information about bioenergy crops’ composition under field conditions is needed to design optimal systems for production, harvesting, storage, and biorefinery operations. In this study, GLBRC researchers used near-infrared spectroscopy and nuclear magnetic resonance spectroscopy to characterize the composition of the energy Sorghum bicolorhybrid TX08001 grown in irrigated and non-irrigated field conditions, providing baseline information for future optimization.

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.