By Sheryl Zhang,
Dec. 9, 2025
On a warm morning in western Kenya, a sweet potato farmer spots a leaf just starting to curl. To the naked eye, the problem looks new. To Julius Lucks, a synthetic biologist at Northwestern University, the virus has already spread — leading to crop loss, replanting and more fertilizer and chemical use than if the early signs had been detected.
“By the time you see symptoms, the virus is already there,” said Lucks, a professor of chemical and biological engineering and co-director of NU’s Center for Synthetic Biology. “It’s been spreading, all sorts of stuff.”
One result of a research approach to detect the virus is Plant-DX, a portable diagnostic Lucks’ team tested with farmers in Kenya. This freeze-dried, paper-based biosensor can be deployed anywhere. Lucks describes freeze-drying biological components as “astronaut ice cream biology”—lightweight, shelf-stable and easy to rehydrate. A farmer can rub a leaf sample into the tube, wait for a color change, and learn whether a virus is present within an hour as simple as a “COVID test,” said Lucks.
Crop loss is not only an economic crisis, but also a sustainability one. Nearly 20 to 40% of global crop production is lost each year to pests and disease, according to the UN Food and Agriculture Organization. That loss pushes farmers to overapply fertilizer, clear more land and increase pesticide use.
Agriculture, forestry and land use together account for 21–37% of global greenhouse gas (GHG) emissions, according to the Intergovernmental Panel on Climate Change. Nitrogen fertilizer alone contributes about 2–3% of global GHG emissions, largely through nitrous oxide released during production and soil breakdown, according to the U.S. Environmental Protection Agency.
Lucks said he believes synthetic biology can help farmers make decisions earlier and more precisely by revealing what their crops need long before visible damage appears. Early, accurate signals reduce waste, prevent unnecessary chemical use and protect yields.
That possibility of making the invisible visible is at the core of how Northwestern researchers envision synthetic biology reshaping agricultural sustainability. Instead of building entirely new crops, they are engineering tools that help farmers act only when action is necessary. Sometimes, that means redesigning how biological systems sense the world and making these tools available to farmers.
“One of the cool things about nature is that it’s super-efficient,” said Madeline Joseph, a fourth-year chemical engineering Ph.D. candidate at Northwestern University. “Biological systems have evolved over millions of years to be very conservative with energy and resources, so we can look to those systems — perfected by environmental and external stressors — to inspire or even use those processes to improve how we manufacture things, how we do agriculture, or really anything in the sustainability realm.”
Joseph studies how biological systems convert raw materials into final products. Unlike traditional chemical processes, which often convert almost everything they take in, biological pathways can be slow or incomplete. But new cell-free systems have achieved surprisingly high yields, sometimes converting more than 70% of the input material into the desired product under optimized laboratory conditions, said Joseph. Higher efficiency means less energy, less waste and fewer agricultural resources consumed upstream.
Joseph said a pathway might look spectacular in a small-scale experiment but fail in a factory or require land-intensive crops such as corn. This is why her work involves life-cycle analysis: evaluating environmental impact from raw materials to disposal.
“I still think there’s a lot of room for improvement. As synthetic biologists, we need to be honest about the use case and the potential impact of our technology,” she said. “We want to make sure that the overall system actually reduces impact.”
Lucks demonstrates the technology’s potential in the field. His lab builds cell-free synthetic biology systems, which remove the molecular machinery from organisms and reassemble it in test tubes. He compares it to “taking the engine out of a car.” The engine still runs on a bench, but scientists can observe, retool, and program it without the constraints of an entire living system.
Plants, Lucks said, are constantly speaking by “sending out alarm signals.” Some signals indicate drought stress; others reveal nutrient deficiencies. In some cases, plants reveal they are “hungry”—starved for nitrogen or other key nutrients. Synthetic biosensors could eventually detect those hunger signals, telling farmers exactly when to apply fertilizer instead of spreading it preemptively.
That precise timing is central to the work of Danielle Tullman-Ercek, professor of chemical and biological engineering and co-director of the Center for Synthetic Biology (CSB) at Northwestern. Her lab studies how engineered microbes and cellular membranes can improve sustainable bioprocessing.
She explained membranes through an analogy. Imagine a building filled with many different “doors,” each controlled by a unique lock. Only certain molecules can move through each door. Engineering microbes to open the right doors at the right moment could allow farmers to use nutrient-releasing microbes that deliver nitrogen slowly and only when crops need it.
This technology avoids the blanket overuse of fertilizer that has defined modern agriculture. Fertilizer transformed global food production, Tullman-Ercek explained, but it was “too blunt a tool” because no one could see what individual plants or microbes were doing inside the soil. Synthetic biology offers a way to give crops a communication system—allowing precise delivery instead of flooding fields with nitrogen.
However, biology doesn’t always behave predictably in the real world. Engineered microbes that thrive in the lab often collapse when introduced into soil. Ashty S. Karim, director of research at CSB, said that soil is a chaotic ecosystem — hot, competitive, teeming with microbes. Introducing a delicate engineered strain into that environment is like “dropping a domesticated pet into the wild.” Many engineered microbes can’t survive long enough to perform their function.
His solution is to skip the organism. Karim builds cell-free enzyme cascades, modular systems that perform chemical reactions using only enzymes, not living cells. He compared them to a Coca-Cola Freestyle machine: a dispenser that mixes dozens of drinks using a small set of base ingredients. Enzyme modules can be swapped and combined to convert waste carbon into valuable agricultural nutrients or chemicals, all without the ecological risk of releasing engineered microbes into soil.
Joseph sees sensing technologies as the most likely near-term impact. Many startups are already developing tools to detect nutrient deficiencies, drought responses, and early infection—tools that help farmers stop guessing.
“If we can give people clearer information, they can make better decisions,” she said.
As synthetic biology moves closer to farms, the researchers emphasized cautious optimism. Public concern over engineered biology remains high, even for cell-free systems that include no living organisms.
As the field advances, the Northwestern team emphasizes that responsible deployment matters as much as scientific progress. They highlight the importance of clear public communication, rigorous evaluation of environmental impacts, designs that reflect on-the-ground realities rather than just laboratory performance, and technologies that remain accessible and practical for farmers.
“Everyone involved needs to have input in discussing the use of the technology,” Karim said. “That’s a really important aspect of any of these technologies being useful.”
Although none of the researchers expect synthetic biology to remake agriculture overnight, they agree it can give farmers better information and clearer options.
Lucks said the goal is simply “empowering farmers with more information,” while Tullman-Ercek noted that biological systems can detect “very specific minute differences” in chemicals that traditional tools miss.
“We don’t have a lot of information about the details of our physical world,” Lucks said. “And without that, we can’t really figure out how to intervene. So I see our work as really filling that information gap.”
Photo at top: The team led by synthetic biologist Julius Lucks tested easy-to-use Plant-DX biosensors in Kenya to detect a crop virus before symptoms show and allow farmers to take action. (Northwestern University McCormick School of Engineering)