A Sweet Path to Renewable Energy

It sounds like modern-day alchemy: Transforming sugar into hydrocarbons found in gasoline. But that’s what scientists have done.

Specifically, they turned glucose (a type of sugar) into olefins (a type of hydrocarbon, and one of several types of molecules that make up gasoline).

The project, co-led by University at Buffalo biologist Zhen Q. Wang, marks an important step forward in efforts to create sustainable biofuels.

The researchers began by feeding glucose to strains of E. coli that don’t pose a danger to human health. “These microbes are sugar junkies, even worse than our kids,” Wang jokes.

The E. coli were genetically engineered to produce enzymes that convert glucose into compounds called 3-hydroxy fatty acids. As the bacteria consumed the glucose, they started to make the fatty acids.

The team then used a catalyst to chemically chop off unwanted parts of the fatty acids, generating the final product: the olefins.

Though olefins comprise a small percentage of the molecules in gasoline, the process the team developed could likely be adjusted in the future to generate other types of hydrocarbons, including some of the other components of gasoline, Wang says. She also notes that olefins have non-fuel applications—they are used in industrial lubricants and as precursors for making plastics.

More research is needed to understand the benefits of the new method and whether it can be scaled up efficiently for making biofuels or for other purposes. One of the first questions that will need to be answered is how much energy the process of producing the olefins consumes; if the energy cost is too high, the technology would need to be optimized to be practical on an industrial scale.

Scientists are also interested in increasing the yield. Currently, it takes 100 glucose molecules to produce about eight olefin molecules, Wang says. She would like to improve that ratio.

Yet, says Wang, this is a promising first step. “Making biofuels from renewable resources like glucose has great potential to advance green energy technology.”