5 Synthetic Biology Discoveries Accelerating Global Sustainability

In celebration of Earth Day and Earth Month, we’ve rounded up five sustainability discoveries made possible by advancements in synthetic biology.

By Kendra Atleework

From the production of rocket biofuel to bioremediation of pollutants, innovations in the field of synthetic biology may seem straight out of science fiction.

Synthetic biology is a cross-disciplinary field focused on reengineering organisms to exhibit new qualities and serve specific purposes. This includes everything from engineering proteins to be able to convert problematic substrates, to synthesizing entire artificial genomes for highly customized microorganism function. Best of all, new synth bio discoveries are making major contributions to sustainability. Read on to learn about some of the incredible, yet very real synthetic biology applications benefitting the environment today.

1. Bacteria, yeast, and rockets: synthetic biology and biofuel innovation

Believe it or not, bacteria may one day send us to space and yeast may power trans-Atlantic flights. As a renewable alternative to fossil fuels, biofuels derived from renewable, organic sources can help reduce greenhouse gas emissions from jets, ships, long-haul trucks, and even rockets. Biofuels have the potential to supply up to 27% of the global demand for transport fuel by 2050. If we reach this milestone, we’ll owe our success in part to microorganisms.

Biofuels have been on scientists’ radar for 150 years, ever since Louis Pasteur discovered that yeasts can produce ethanol from sugar. Historically, the cost of biofuels has been much higher than that of fossil fuels. In the future, that cost gap may close thanks to improvements in genetic sequencing, microbes such as bacteria and yeasts that can be genetically modified to optimize the production of bioethanol, biobutanol, and biodiesel, among others.

Recent improvements in tools that reprogram cell metabolism have made these single-celled biofuel “factories” possible. These biofuel “factories” consisting of genetically modified microorganisms support sustainability and are easy to customize and scale. And, unlike fuels like biodiesel made from edible plant oils and ethanol made with corn, they don’t compete with food production. Instead, these bacteria can be fed with plant matter, including agricultural residue and brush removed to prevent wildfire, thus reaping the perks of CO2 capture.

Other biofuel experts have an eye on outer space. Researchers are using bacteria to create fuel with a greater energy density than almost anything available today—even rocket fuel. The bacteria recruited for this task, Streptomyces, can be found in soil all over the world.

Relying on biofuels won’t come with sacrifices in fuel quality. Since the chemical structures of biofuels can be more tightly controlled, fuels produced by genetically modified bacteria can be even better than their petroleum-derived counterparts.

2. Plants to the rescue: synthetic biology, carbon capture, and GMO trees

There’s a new kind of poplar tree growing in research sites. Researchers have genetically modified poplars to grow faster and larger than unmodified poplars, thus sequestering greater amounts of carbon.

Carbon capture is something that any tree can do, but as trees and other plants convert carbon into sugars and other nutrients, they also produce a toxic byproduct that must then be broken down during photorespiration, an energy intensive process that ends up releasing a portion of sequestered CO2.

What sets these new poplars apart? They boast three inserted genes, borrowed from squash and algae, which allow them to minimize the photorespiration process, thus channeling more energy into growth. Compared to standard poplars, the modified trees can grow up to 53 percent larger in five months and can capture 27 percent more CO2. Researchers project that, once planted at scale, these genetically modified trees may remove billions of tons of carbon dioxide from the atmosphere. Time will tell if genetically modified trees will offer a viable approach to carbon capture or disease resistance in the future.

3. Roots, shoots, and carbon capture

When it comes to carbon sequestration, the bigger the root system the better. Thanks to progress in synthetic biology, genes controlling biomass distribution can now be identified and modified, with the added perk of restoring carbon to depleted soils.

Genetic modification of plants can help out in other areas, too. Modification of plants for better flood and drought resistance can enable precision agriculture and boost productivity. And thanks to synthetic bio innovations, more food plants can be modified to work double duty. Research suggests the possibility of imparting the nitrogen-fixing abilities of legumes to other crops, including cereals. While providing a significant portion of the world’s food supply, non-leguminous crops like wheat and oats usually require exogenous nitrogen to be productive. Genetic modifications of these cereal crops could enable plants to self-fertilize while removing a particularly nasty and persistent greenhouse gas from the environment. Similarly, the genes of fast-growing ferns and algae can be adjusted to draw down atmospheric CO2.

4. Decarbonizing chemical production: harnessing synthetic biology for more sustainable manufacturing

The production of non-fuel chemicals, from plastics to industrial chemicals, has proved one of the hardest industries to decarbonize. The industry is the biggest consumer of oil and gas and also the third highest emitter, behind only cement production and steel and iron mills. But synthetic biology has the potential to limit emissions from chemical manufacturing.

Historically, even manufacturing using microorganisms contributed to the release of greenhouse gases, largely because the microorganisms in use were fed on sugar, an environmentally costly product. Now, researchers are working hard to enlist the help of acetogens, autotrophic bacteria that survived on earth before the atmosphere contained oxygen.

Crucially, acetogens don’t suffer from a sweet tooth: these bacteria thrive on post-combustion CO₂. With some modification, waste gases from industrial facilities such as petroleum refineries can provide a feast. Thanks to recent synthetic biology breakthroughs, acetogens have been engineered to facilitate efficient, large-scale production of acetone and isopropanol. Acetogens are flexible, too—depending on the desired product, manufacturers can switch between different strains, with plenty of potential for expansion.

5. Synthetic bio cleanup crews: bioremediation with microbes

Since around the year 1900, industrialized society has released organic pollutants and anthropogenically derived chemicals into the environment at a problematic rate. In the same span of time, microorganisms have evolved with the ability to make the most of these pollutants. Now, synthetic biology offers ways to harness microorganisms to help with the dirty work of bioremediation, making the planet cleaner and safer for everyone.

Microorganisms can be engineered to produce enzymes that degrade contaminants in extreme environments where many other proteins would denature, such as halophilic bacteria engineered to break down petroleum and polycyclic aromatic hydrocarbons from extremely saline wastewater. Microorganisms can also assist with the cleanup of pollutants dispersed across large areas—tasks that may otherwise be prohibitively challenging and costly.

Engineered organisms can help clean up military land polluted with compounds from explosives. And researchers are at work developing enzymes that can serve as biosensors, alerting industries to the presence of harmful chemicals such as p-nitrophenol in industrial wastewater and mine effluent. Development is also underway for organelles that can collect and store waste particles, including toxic metal contaminants. Researchers are exploring the potential of inserting an extracellular protein nanofiber into E. coli bacteria that can in turn absorb mercury.

In case we needed more reasons to be excited about synthetic biology, even the global plastic problem stands to benefit, as researchers undertake the study of enzymes exhibiting activity toward a variety of polymers. While bioremediation is in its infancy, improved DNA sequencing and synthesis technologies are allowing researchers to embark on innovative solutions to big problems.

Conclusion

The dangers faced by today’s environment are many, and the potential to engineer customizable solutions sounds almost too good to be true. While the field of synthetic biology is young, it’s also incredibly promising. With wide-scale, organized application and collaborative engineering between policy makers, scientists, and industry leaders, synthetic biology offers considerable potential to achieve lasting sustainability without disrupting modern industry, enabling a cleaner, safer future for this planet, and everyone on it.

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References

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Liu, Zihe, Hamideh Moradi, Shuobo Shi, and Farshad Darvishi. 2021. “Yeasts as Microbial Cell Factories for Sustainable Production of Biofuels.” Renewable and Sustainable Energy Reviews 143 (June): 110907. https://doi.org/10.1016/j.rser.2021.110907.

Magazine, Smithsonian, and Margaret Osborne. 2023. “Genetically Modified Trees Are Taking Root to Capture Carbon.” Smithsonian Magazine. February 21, 2023. https://www.smithsonianmag.com/smart-news/genetically-modified-trees-are-taking-root-to-capture-carbon-180981675/.

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