Reviewed by Lexie CornerMar 5 2025
Researchers from the University of Cincinnati and the US Department of Energy's Oak Ridge National Laboratory have made progress in understanding how microbes respond to the alcohols they produce. This occurs during the fermentation of plant biomass.
The team focused on the fermentation of butanol, a biofuel with a high energy density that can also be used as a solvent or chemical feedstock. Using neutron scattering and simulation tools at the national lab, the researchers studied the interaction between microbes and butanol during fermentation.
Butanol itself is toxic to the microbes that produce it. According to Jonathan Nickels, Associate Professor of Chemical and Environmental Engineering at UC's College of Engineering and Applied Science, this toxicity limits the amount of butanol that can be produced during fermentation, presenting a challenge for bio-based production.
The primary location of toxicity is in the membrane. Ultimately, the solvent thins it out and makes it softer and less stable. Ultimately, you get holes in the membrane. When this happens, the cell loses the ability to generate energy.
Jonathan Nickels, Associate Professor, Chemical and Environmental Engineering, University of Cincinnati
Butanol tends to accumulate unevenly around the membrane, which leads to variations in thickness. This uneven distribution can cause cell stress and reduce the efficiency of fermentation.
Luoxi Tan, Lead Author of the study and a Postdoctoral Researcher at the National Laboratory, continues this collaboration. Tan, who earned his Doctorate from UC's College of Engineering and Applied Science, stated that scientists are now focusing on determining whether stabilizing the cell membranes in biomass can improve the efficiency of biofuel production.
(The findings) provide us with new targets to reduce the influence of these fermentation products.
Luoxi Tan, Study Lead Author, University of Cincinnati
Researchers used neutron scattering experiments, which allow for non-destructive testing of membranes. These experiments also reveal the molecular structures and arrangements during the fermentation process.
Neutrons give you the ability to probe the interior of the membrane to help determine how the butanol is distributed.
Hugh O’Neill, Director, Center for Structural Molecular Biology, Oak Ridge National Laboratory
To study how atoms and molecules move and interact over time, researchers ran molecular dynamics simulations on supercomputers. These simulations allowed scientists to observe the molecular changes occurring in a cell's membrane structure.
According to Nickels, “The findings have very relevant and meaningful long-term implications. We want to make biofuels more efficient, which would have significant economic outcomes.”
Nickels also expressed his pride in his longstanding partnership with Oak Ridge: "It is a great collaboration. Working with world-leading scientists and staff at a national lab is a tremendous privilege. And it provides inspiration and an environment for great work for a student's doctoral research.”
The national lab’s Center for Structural Molecular Biology supported the study.
Journal Reference:
Tan, L., et al. (2025) Toxic Effects of Butanol in the Plane of the Cell Membrane. Langmuir. doi.org/10.1021/acs.langmuir.4c03677.