Scientists at Xylofuel LLC, a startup from Columbia, MD, discovered microorganisms that convert carbon dioxide and hydrogen to alcohols and hydrocarbons similar to the components of gasoline. The gases are inexpensive to produce as industrial byproducts or from heating or anaerobic digestion of biomass. The fuels produced by microbial isolates include hexane and other medium length alkanes.
The organisms were isolated from a cow’s first stomach chamber or rumen. The reason cows can digest grass is because billions of microorganisms that live inside the rumen convert plant fiber to organic acids and gases like carbon dioxide and hydrogen. Other microorganisms convert the carbon dioxide and hydrogen to methane and other products while the cow gets most of its energy from the acids.
Knowing that the cow produced thousands of liters of these gases everyday, Xylofuel scientists investigated whether any organisms in the rumen could convert the gases to alcohols or hydrocarbons. First they tweaked the conditions of the fermentation in a test tube using microbes from the cow. They discovered the microbial cultures could be made to release short hydrocarbons like propane or butane, and even longer hydrocarbons like hexane.
Once the conditions were identified that caused the fermentation to shift to release these compounds, microbes were isolated that were responsible for making the hydrocarbons. Xylofuel had isolated additional microbes that produced alcohols like ethanol and 1-butanol.
Xylofuel, LLC, is a start-up company that was founded two years ago by Animal Science Professor Rick Kohn from the University of Maryland. Dr. Kohn hopes to refine and scale up various processes to produce fuels and other products from biomass or inexpensive gases. Dr. Kohn studied fermentation in the cow’s rumen for twentyfive years and developed mathematical models to explain fermentation patterns. He was assisted by Dr. Seon-Woo Kim, a rumen microbiologist and native of South Korea.
[thanks to Prof. Rick Kohn]