The Biofuels SFA led by Oak Ridge National Laboratory (ORNL) conducts fundamental research underlying efforts to improve the production efficiency of biofuels and bioproducts. Emphasis is on understanding the potential of co-solvents (red) to disrupt both microbial cell membrane lipid bilayers (left) and plant biomass components (right) composed of cellulose fibers (green) and lignin (yellow). [Courtesy ORNL]
The Biofuels Science Focus Area (SFA) at Oak Ridge National Laboratory aims to provide fundamental knowledge about how solvents alter the structure and arrangement of critical biomolecular assemblies that comprise plant cell walls and microbial membranes. Efficient and economical conversion of lignocellulosic biomass into advanced biofuels and bioproducts requires pretreatment of biomass and microbial fermentation, processing steps critical to achieving high product titers. Improvements are needed to address key limitations in these conversion processes. The SFA seeks detailed information on the extent of disruption of biomass or biomembranes and will elucidate the molecular forces involved. This information will help determine the ultimate biological limits of microbial tolerance to high levels of specific solvents. Comparable information will aid in the choice or eventual design of co-solvents best suited for pretreatment. The design of co-solvent pretreatment regimes will thus be rationally informed, permitting the use of bioenergy feedstocks to produce bioproducts with properties tailored to desired downstream applications.
Solvent disruption phenomena will be studied at multiple spatial scales using neutron scattering and high-performance computer simulations complemented by expertise in biodeuteration, bacterial membrane engineering, and plant cell wall physical chemistry. The SFA team proposes that the disruption of biomolecular assemblies that form biomass and biomembranes can be understood through mechanisms of amphiphilic co-solvents interacting with different hydrophobic or hydrophilic regions of these structures. Amphiphilic solvents like ethanol, butanol, or tetrahydrofuran have both hydrophobic and hydrophilic properties. The overarching hypothesis is that amphiphilic solvents are well suited for maximal disruption of biomass and biomembrane structures.
Specific SFA goals are to integrate predictive computational models, biophysical characterization (neutron scattering and nuclear magnetic resonance), and synthetic biology to understand membrane resistance to solvents, identify the solvent properties best-suited for biomass disruption and fractionation, and determine whether amphiphilic solvents are the most disruptive.