Plastics from CO2-using Nano-bugs
- Elements of Science
- Aug 4, 2019
- 3 min read
Updated: Aug 28, 2019
June 11, 2019
Over the past century, the concentration of carbon dioxide (CO2) in the atmosphere has increased to an all time high as of 2017 of 405 parts per million[4]. This is to say that for every million particles or molecules in the air, 405 of those are carbon dioxide molecules, which accounts for less than 1% of the air. Despite this unalarming number, this concentration of carbon dioxide has caused higher earth temperature and even changes in the weather pattern. This number continues to increase daily and is growing at the fastest rate recorded in history[4]. Carbon dioxide is created by burning fossil fuels, which includes coal and natural gas, to produce heat or to create electricity. This large quantity of carbon dioxide is what causes the greenhouse gas effect, resulting in the increase in global temperatures that lead to rising sea levels and drastic weather changes.
Many scientists are researching more environmentally-friendly ways to produce energy without burning fossil fuels like making more efficient solar panels or improving electrolysis. Electrolysis is a method of creating gaseous fuel, like hydrogen gas, by running current through a liquid to cause a reaction. These methods take a more direct approach by trying to elimnate the production of carbon dioxide. On the other hand, a group of scientists in the Nagpal group from the University of Colorado Boulder are taking a different approach to fixing the excess carbon dioxide issue by looking for ways to consume the extra carbon dioxide that is present in the atmosphere. The group has found a way to produce nanobio-hybrid organisms that they call nano-bugs that can consume carbon dioxide to produce plastics or even eco-friendly fuels. This is done through the usage of light-activated quantum dots that are integrated into microbial species[1][2].
Quantum dots are nanoparticles of semiconductors that contain a variety of properties depending on their shape, size, composition, and structure. These quantum dots can be manipulated to be only activated at a certain energy level, which in our case corresponds to a certain wavelength of light[3]. This means that if a quantum dot was designed to absorb green wavelengths, it would only absorb the green wavelength of light and not any other. Quantum dots alone cannot produce biodegradable plastics or fuels. These products are created by microbial species located inside the soil. These microbial species are known to produce various products by consuming gases like carbon dioxide or nitrogen gas. An example of these microbes can be the nitrogen-fixing that can be found in the soil of your backyard. These nitrogen-fixing microbes are important because they convert the nitrogen gas in the air into ammonia, which gives the plants a source of nitrogen allowing for more seed production and fruiting. The production of goods like biodegradable plastics or fuels are activated through light sensitive enzymes. However, with a lack of light in soil or at the bottom of ponds, these microbes are not always active causing slow production of biodegradable plastics or fuels[2].
By embedding quantum dots into these microbes, these scientists designed a nano-bio hybrid organism that is more active than a natural microbe. This increased activity allows for noticable production of biodegradable plastics through carbon dioxide consumption as seen from the image above. Through the combination of quantum dots and specific microbes, the enzymes in the microbes are more consistent active. This is all attributed to the embedded quantum dots that store light energy and re-release them to the enzymes in the microbes at a slower rate to keep the microbes active. This stored energy by the quantum dots allows for an extended time of activation that can lead to more than 200% of the natural yield of these nano bugs, according to Professor Prashant Nagpal[1][2].
This form of biotechnology through nano-bugs would help solve the buildup of greenhouse gases by consuming carbon dioxide but at this time, it is not as efficient to use these nano-bugs because of the production time and resources that are required to maintain and support the microbes. Despite these downsides, this technology could be integrated into small towns that allow homes to pump their carbon dioxide to local ponds where these nano-bugs are housed to produce biodegradable plastics[1][2]. This could allow for green communities, which is a step in the right direction to improve carbon dioxide concentrations on earth.
By David Zheng
Works Cited
- Colorado State University article on nano-bugs. Image of plastics and microbe system.
- Article providing more information about nano-bugs
- Website dedicated to quantum dots
- NASA data about carbon dioxide emissions
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