Researchers are constantly searching for new and inventive ways to develop cleaner plastics and bio-fuels to solve some of the pollution problems the world faces.
As part of this effort, researchers at Colorado University Boulder have developed perhaps one of the most interesting inventions thus far—nanobio-hybrid organisms that “eat” airborne carbon dioxide and nitrogen and can use it to produce a variety of plastics and fuels.
A team in CU Boulder’s Department of Chemical and Biological Engineering led by assistant professor Prashant Nagpal developed the nano-bugs, which researchers believe could be a promising first step toward low-cost, eco-friendly manufacturing for what are currently harmful chemicals.
The research dates back to 2013, when Nagpal and colleagues first began to explore the potential of what are called nanoscopic quantum dots—tiny semiconductors similar to ones found in television sets.
These dots can be injected into cells to attach and self-assemble to desired enzymes and then activate these enzymes on command using specific wavelengths of light.
A gram of biodegradable plastic created by nanobio-hybrid microbes developed by CU Boulder engineers. (Image Source: Nagpal Lab / University of Colorado Boulder)
idea—manifested in the team’s latest work—was to use the dots as a catalyst to “fire” certain enzymes in microbials that could convert airborne carbon dioxide and nitrogen. Researchers used light-activated quantum dots to fire these enzymes to create “living factories” that consume harmful carbon dioxide and then convert it into useful products, such as biodegradable plastic, gasoline, ammonia, and biodiesel, Nagpal said.
“The innovation is a testament to the power of biochemical processes,” he said. “We’re looking at a technique that could improve carbon dioxide capture to combat climate change and one day even potentially replace carbon-intensive manufacturing for plastics and fuels.”
Carbon Dioxide as Food for Fuel
The team achieved their results by diffusing specially tailored dots into the cells of common microbial species found in soil. This caused a scenario in which exposure to even small amounts of indirect sunlight activated the microbes’ appetite for carbon dioxide independent of an energy source or food to carry out the energy-intensive biochemical conversions, Nagpal said.
“Each cell is making millions of these chemicals and we showed they could exceed their natural yield by close to 200 percent,” he said.
How the process works is that the microbes lie dormant in water, releasing their resulting products to the surface. Here they can be skimmed off and harvest for manufacturing.
Researchers also discovered that they can create different products using different combination of dots and light, Nagpal said. For instance, green wavelengths cause the bacteria to consume nitrogen and produce ammonia, while redder wavelengths cause the microbes to eat carbon dioxide to produce plastic. The team published a paper on their research in the Journal of the American Chemical Society.
“We were very surprised that it worked as elegantly as it did,” Nagpal said. “We’re just getting started with the synthetic applications.”
Nagpal has high hopes for the technology. He envisions a future with homes and businesses that pipe their carbon-dioxide emissions directly to a nearby holding pond, with microbes waiting to turn them into a bioplastic. Home and business owners could sell the product while at the same time reducing their own carbon footprint, he said.
“Even if the margins are low and it can’t compete with petrochemicals on a pure cost basis, there is still societal benefit to doing this,” Nagpal said. “If we could convert even a small fraction of local ditch ponds, it would have a sizeable impact on the carbon output of towns.”
Elizabeth Montalbano is a freelance writer who has written about technology and culture for more than 20 years. She has lived and worked as a professional journalist in Phoenix, San Francisco and New York City. In her free time she enjoys surfing, traveling, music, yoga and cooking. She currently resides in a village on the southwest coast of Portugal.
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