Researchers at LanzaTech, a synthetic biology company in Illinois, have developed the bacterium Clostridium autoethanogenum to ferment carbon monoxide and carbon dioxide into everyday chemicals such as acetone and isopropanol, which are used in disinfectants and medical alcohols, and are the basis for acrylic glass and polypropylene plastics. .
This process uses CO and CO2 to create a beneficial by-product that makes it carbon negative, meaning it can reduce the amount of carbon dioxide vented into the atmosphere, which contributes to warming and therefore climate change.
Traditionally, acetone and isopropanol (aka isopropyl alcohol) are resource-intensive by-products that require a lot of fossil fuels to produce. Acetone is obtained from the raw materials of benzene and propylene. According to scientists, the combined global market for these large industries is more than $10 billion.
Researchers have found a cleaner way to produce these chemicals, which could help rid the atmosphere of carbon dioxide. During fermentation, the yeast “eats” the sugar and produces ethanol. In this similar process, the bacterium was engineered to feed on CO and CO2 and produce these chemicals. In its pre-engineered natural form, it creates ethanol. Using synthetic biology, the bacterium can now produce acetone.
“Our motivation was to find an abundance of feedstock,” said Michael Koepke, author of the article and director of synthetic biology at LanzaTech.
According to Koepke, traditional production methods emit large amounts of CO2 into the atmosphere. A typical car emits almost 9 kg of CO2 per gallon of gasoline, which means that one car can emit about 4.6 metric tons per year. Given that acetone and isopropyl alcohol are two of the most commonly used chemicals in everyday products, the amount of carbon dioxide added to or removed from the environment is staggering, scientists say.
Acetone and isopropyl alcohol – according to the researchers – this is just the beginning.
“What’s interesting is that we think these same tools can be used to adapt a wide variety of commercial chemicals to this carbon-negative manufacturing approach,” said co-author Michael Jewett, professor of chemical and biological engineering at Northwestern university.
The traditional processes for creating acetone and isopropyl alcohol from raw materials have been perfected for decades, so they are optimized for the market – unlike the new process.
The next step will be to expand the process further to make it a mainstream industrial tool.
Koepke also expressed hope that scientists will continue to study other bacteria as channels for the fermentation of CO and CO2 into valuable products – in addition to ethanol, acetone and isopropyl alcohol.