Researchers from the Department of Energy’s Oak Ridge National Laboratory (ORNL) and the University of Cincinnati have recently achieved a scientific breakthrough that could lead to more efficient production of biofuels, like butanol. According to a study published in the journal Langmuir, the team used neutron scattering and molecular dynamics simulations to understand how butanol affects the microbes that produce it during fermentation.
Butanol presents a double-edged sword; it's an energy-packed alcohol useful as a biofuel, solvent, or chemical feedstock, yet it's toxic to the microbes responsible for its production. This toxicity limits fermentation efficiency, which is a significant hurdle in bioproducts development. “This could be a new fundamental mechanism for solvent toxicity, where the solvent does not have to disrupt the ‘bulk’ membrane but, rather, targets a ‘weak’ spot in the membrane — the domain interface,” Brian Davison, chief scientist for systems biology and biotechnology and lead for the Biofuels Science Focus Area (SFA) at ORNL, told ORNL's official news publication.
The researchers used the Bio-SANS instrument at the ORNL to analyze the effects of butanol on the microbes' cell membranes. Neutron scattering provided a non-invasive method to see molecular structures and arrangements, offering insights into how increased amounts of butanol cause membrane domains to merge. Hugh O'Neill, project collaborator and CSMB director at ORNL, explained in a statement obtained by ORNL that neutrons “give you the ability to probe the interior of the membrane to help determine how the butanol is distributed.”
Complementing the practical observations, molecular dynamics simulations were run on a supercomputer at the National Energy Research Scientific Computing Center, which produced a complete, atomistic picture of the molecular interactions. According to Jon Nickels, principal investigator and associate professor of chemical and environmental engineering at the University of Cincinnati. He explained, “a complete atomistic picture that can tell us a great deal about these systems and guide future experiments,” highlighting the precision these methods add to the research.
This discovery opens the door to potential solutions, such as engineering microbial strains with more resilient membranes or utilizing microorganisms naturally tolerant to butanol. Luoxi Tan, the first author and a postdoctoral researcher at ORNL, expressed optimism in a quote shared by ORNL, saying, “We now know to ask if more stable membrane domains could significantly reduce cell stress during fermentation, resulting in more efficient conversion and higher butanol titers.” The findings represent a blend of high-level biology with computational and neutron science, exemplifying the powerful synergy between academia and national laboratories.
