From Carbon Monoxide to Ethanol - A New Method for Producing Biofuel
Shane Laros posted on October 04, 2016 |
Developing new biofuels is a project that has many engineers working overtime, as many believe that breaking humanity's dependence on fossil fuels is essential to our continued survival.

In light of this, researchers at Cornell University have developed a new way of creating ethanol—a common ingredient in both adult beverages and biofuels—by way of microbes that eat carbon monoxide.

While repurposing both organic and non-organic waste into biofuel has been researched in the past, the Cornell team has made strides in understanding the physiological process underlying ethanol fermentation in the hope of expanding the current biofuel production industry.

The team from Cornell's Atkinson Center for a Sustainable Future have been using the bacterium Clostridium ljungdahlii, which responds thermodynamically rather than genetically, in the process of tuning favorable enzymatic reactions.

They found that the microbe consumes and then ferments carbon monoxide gas by bubbling it in a growth medium solution, where the cells can feed on it.

Clostridium ljungdahlii bacteria. (Image courtesy of University of Oklahoma/University of Illinois.)
Clostridium ljungdahlii bacteria. (Image courtesy of University of Oklahoma/University of Illinois.)
According to Ludmilla Aristilde, assistant professor in biological and environmental engineering, "The microbial cells then turn it into ethanol, an organic molecule. And carbon monoxide, an inorganic molecule, turns into something valuable we can use. That's what makes this special."

"Instead of having the waste go to waste, you make it into something you want," said Aristilde.

"In order to make the microbes do our work, we had to figure out how they work, their metabolism."

Aristilde collaborated with Lars Angenent, professor of biological and environmental engineering, on the project. He noted that their insights are particularly important to the further improvement of the synthetic gas, or syngas production industry.

The study, "Ethanol Production in Syngas-Fermenting Clostridium ljungdahlii Is Controlled by Thermodynamics Rather Than by Enzyme Expression" was published in the journal Energy and Environmental Science.

For more on biofuel, check out this article on sustainable beer.

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