Mushrooms may be trending in haute cuisine, but wearing them could be the next hot thing. It’s a fashion future Vayu Hill-Maini, PhD, assistant professor of bioengineering, and Xiaojing Gao, PhD, assistant professor of chemical engineering, are working to bring about with synthetic biology, an emerging field that combines principles from biology, engineering and chemistry to redesign or create organisms for useful purposes.
Think mRNA vaccines, biofuels and cell-cultured meat.
Hill-Maini and Gao are conducting research on the production of aesthetically pleasing and environmentally sound textiles made of fungi. “Hopefully, in two years, I’ll be wearing a cool fungal suit,” Hill-Maini said May 7 at Stanford’s second Synthetic Biology for Sustainability Symposium in Paul Brest Hall. “Don’t hold me to it, but that’s kind of the vision.”
Supported by the Stanford School of Medicine, the School of Engineering and the Doerr School of Sustainability, the symposium featured speakers from a range of departments across the university discussing ways synthetic biology can promote a sustainable world.
“At Stanford, where interdisciplinary studies and collaboration at all levels —between fields, between faculty, between students and trainees — are so highly valued, it makes a lot of sense that a core area of focus would be synthetic biology and its applications,” said Lloyd Minor, MD, dean of the School of Medicine and vice president for medical affairs at Stanford University.
Hill-Maini and Gao’s fungi project is one of several multidisciplinary projects to have been awarded seed grants by the Stanford Synthetic Biology for Sustainability grant program. The projects, several of which were discussed at the symposium, bring together researchers from different disciplines to create environmentally friendly, sustainable alternatives to things like fertilizers and building materials.
“About 20 years ago, when our bioengineering department was created, I think many engineers, even some bioengineers, didn’t realize how important bioengineering and synthetic biology in particular would be to the challenges that are facing our planet,” said Jennifer Widom, dean of the School of Engineering. (The bioengineering department is jointly operated by the schools of medicine and of engineering.)
She added, “Those challenges are really significant. They’re really complex. They require a multidisciplinary approach.”
Following are descriptions of some of the projects that have received Synthetic Biology for Sustainability seed grants.
Lab meat (that actually tastes good). Helen Blau, PhD, professor of microbiology and immunology; Sarah Heilshorn, PhD, professor of materials science and engineering
Meat production takes a big toll on the environment. It’s a source of greenhouse gases, water pollution, deforestation and desertification. Yet global meat consumption is on the rise. That’s why Blau and Heilshorn have joined forces to experiment with producing a lab-cultured meat. The process is called cellular agriculture. Others have made a go at it, but their products have often turned out pasty and unappetizing. Blau and Heilshorn are culturing bovine muscle satellite cells in a scaffold made from an engineered protein with the goal of a more palatable product. To turn beef-ish paste into a something resembling a steak, and do it at scale, they are experimenting with bioprinting, a type of 3D printing that can create complex, tissue-like structures.
Proteins for mineral extraction. Possu Huang, PhD, assistant professor of bioengineering; Tianyu Lu, bioengineering graduate student; Danielle Mai, PhD, assistant professor of chemical engineering
Extracting critical minerals and rare earth elements relies on petroleum products, such as kerosene, for their purification and refinement. The process produces plenty of toxic waste — an irony, given the minerals and elements are largely destined for use in the clean-energy economy. Huang, Lu, Mai and their team are pursuing a more sustainable approach through synthetic biology. Building on the discovery of a naturally existing protein that can be used to more cleanly separate two rare earth elements, they are training a diffusion model, a type of machine learning system, to design protein structures with ideal binding geometries of other critical minerals. They also hope the platform will make conventional extraction of critical minerals less energy intensive and provide a way to extract critical minerals from unconventional sources, such as fly ash (a product of coal-fired power plants) and electronic waste.
Artificial nitrogen-fixation in plants. Ellen Yeh, MD, PhD, associate professor of pathology and of microbiology and immunology; Jennifer Brophy, PhD, assistant professor of bioengineering
Plants need nitrogen, but they can’t just take it from the air. They can access it only when in a “fixed” form, such as ammonium nitrate, which they can absorb through their roots. Commonly this might be solved by using nitrogen-laden fertilizers, but excess nitrogen from fertilizers can find its way to the ocean and other bodies of water, prompting algal growth, whose decomposition depletes the oxygen supply used by marine life, causing dead zones. Yeh and Brophy have engineered plant organelles, a structure inside a cell, that contain a nitrogen-fixing bacteria. The goal is to let plants create their own useable nitrogen, decreasing reliance on fertilizers.
Converting plastic waste into palm oil components. Matteo Cargnello, PhD, associate professor of chemical engineering; Jennifer Cochran, PhD, professor of bioengineering
Plastic recycling poses a variety of problems. Plastic degrades after use, meaning a plastic water bottle can’t be turned into another water bottle. It’s expensive to collect and sort. And different types of plastics don’t mix well when melted down together. In reality, most plastic ends up in a landfill, and a lot makes its way into the ocean. Cochran and Cargnello are experimenting with breaking down plastics into their component parts. They are using green hydrogen to break down polyethylene, a widely manufactured plastic, into hydrocarbons, which microbes can convert to components of palm oil, including palmitic acid and stearic acid. As manufacturers of palm oil raze forests to plant palm trees, and discarded polyethylene continues to contaminate the planet, this project could lead to results that help protect the environment on both fronts.
Reprogramming dandelions for large-scale rubber production. Jennifer Brophy, PhD, assistant professor of bioengineering; Rene Inckemann, PhD, postdoctoral scholar in bioengineering; Xiaojing Gao, PhD, assistant professor of chemical engineering
Natural rubber used for commercial purposes comes from a single tropical tree, and since 1993, nearly 10 billion acres of rainforest have been cut down for rubber tree farming. Some 50,000 different products are made with natural rubber that cannot be replaced with synthetic rubber. Brophy, Inckemann and Gao believe it’s critical to find an alternative source of natural rubber. And while there are about 2,500 plant species that make some type of rubber, only one — a dandelion species native to Kazakhstan — produces a kind for which there’s demand. The team is conducting research on how to re-engineer and reprogram the architecture of these dandelions so they’re better suited for automated, large-scale farming.
Hanae Armitage, associate director of content strategy in the Stanford Medicine Office of Communications, contributed to this report.
