Scientists engineer microbial teams to transform mixed plastics into valuable products

Scientists engineer microbial teams to transform mixed plastics into valuable products

La Jolla, California-December 11, 2025-Each year, the world produces more than 400 million metric tons of plastic, much of which ends up in landfills, incinerators, or the natural environment. While recycling programs exist, they are often limited in scope and effectiveness, especially when it comes to the most difficult category of waste: mixed plastics. Now, a team of researchers led by Tae Seok Moon at the J. Craig Venter Institute and Moonshot Bio, Inc. has developed pioneering biotechnology that can convert mixed plastic waste into valuable chemicals, offering a promising new solution to this global problem.

Most plastic recycling and upcycling technologies focus on "single-stream" plastics-waste composed of just one type of polymer, such as PET (polyethylene terephthalate, commonly found in water bottles) or HDPE (high-density polyethylene, used in milk jugs). These processes rely on the ability to sort and separate plastics-which is both labor-intensive and expensive-as each type requires different chemical treatments.

As a result, most mixed plastics are either incinerated or landfilled, neither of which are desirable outcomes from an environmental or economic standpoint. The inability to efficiently process mixed plastic waste is a major bottleneck in achieving a sustainable, circular economy for plastics.

The research team's new process tackles this challenge head-on by combining chemical and biological innovations. First, mixed plastics are subjected to a chemical pretreatment that breaks them down into smaller, biocompatible molecules. Unlike many existing methods, this process avoids the use of toxic transition metals, relying instead on oxidative degradation with nitric acid or p-toluenesulfonic acid. The result is a diverse mixture of "oxygenates"-small organic molecules that can serve as food for microbes.

But the real breakthrough comes in the next step: the use of an engineered microbial consortium. Rather than relying on a single type of microbe, the team designed a partnership between two bacterial specialists: Rhodococcus jostii (which excels at breaking down aromatic compounds) and Acinetobacter baylyi (which specializes in aliphatic acids). By dividing the labor, these microbes can efficiently consume the full spectrum of molecules produced from mixed plastics, regardless of the variability in the plastic waste composition.

This division of labor is key. Previous efforts to upcycle plastics using single microbial strains required extensive genetic modifications to enable the breakdown of complex mixtures, often resulting in metabolic stress and reduced efficiency. In contrast, the consortium approach leverages the natural strengths of each microbe, creating a robust and adaptable system.

Once the microbial team has consumed the plastic-derived molecules, it transforms them into valuable products. In these studies, the researchers focused on two: lycopene and lipids. Lycopene is a red pigment found in tomatoes and other fruits, prized for its antioxidant properties and used in food, supplements, and cosmetics. Lipids are fats and oils that serve as essential energy sources in living organisms and have wide applications in food, cosmetics, and biofuels.

This process is known as waste valorization, the conversion of low-value or problematic waste materials into higher-value products. By turning mixed plastic waste into lycopene and lipids, the researchers not only address the pollution problem but also create new economic opportunities.

"Our work demonstrates that by harnessing the power of engineered microbial communities, we can turn even the most challenging mixed plastic waste into valuable resources," said Tae Seok Moon, senior author and professor at the J. Craig Venter Institute. "This is a critical step toward a truly circular economy, where waste becomes a feedstock for sustainable manufacturing."

The concept of a circular economy is central to this work. In a circular economy, resources are kept in use for as long as possible, and waste is minimized through recycling, repair, and upcycling. This stands in contrast to the traditional "take-make-dispose" model, which relies on extracting raw materials, manufacturing products, and discarding them after use.

By enabling the upcycling of mixed plastics, the new technology helps close the loop, transforming what was once considered unrecyclable waste into feedstock for sustainable manufacturing.

One of the most impressive features of the microbial consortium is its robustness. The team found that the system could efficiently process mixed plastic waste with fluctuating compositions, maintaining its metabolic capabilities and population balance for at least 21 days. This adaptability is crucial for real-world applications, where the composition of waste streams can vary widely.

The researchers also performed sensitivity analyses, showing that the consortium could tolerate significant variations in the types and amounts of plastics present, further demonstrating its potential for large-scale deployment.

This research builds on previous work by the team, which focused on the biological upcycling of single-stream plastics like PET. In this study, engineered microbes were able to convert PET waste into valuable chemicals. The current breakthrough extends these methods to real-world, mixed plastic waste, making the process more practical and scalable.

This innovation is part of the ongoing Center for Innovative Recycling and Circular Economy (CIRCLE), a multi-year initiative funded by the National Science Foundation. The CIRCLE project aims to revolutionize recycling by developing new technologies for upcycling diverse plastic waste streams, with the goal of supporting a truly circular economy.

The researchers envision that their microbial consortium platform could be adapted for other waste streams, such as wastewater treatment and bioremediation, further expanding the impact of biotechnology on environmental sustainability. Ongoing work will focus on optimizing the process for industrial applications and exploring new products that can be made from recycled plastics.

The complete study, "Engineering microbial consortia for mixed plastic upcycling," may be found in the journal Nature Communications. This breakthrough achievement was possible thanks to academia-industry collaborations among J. Craig Venter Institute, NC State University, Washington University in St. Louis, and Moonshot Bio, Inc. Funding for work provided by the U.S. Department of Energy (DE-SC0022003), the National Science Foundation (EF-2222403 and OISE-2435184), and the American Institute of Chemical Engineers (Langer Prize for Innovation and Entrepreneurial Excellence).

About J. Craig Venter Institute

The J. Craig Venter Institute (JCVI) is a not-for-profit research institute in Rockville, Maryland and La Jolla, California dedicated to the advancement of the science of genomics; the understanding of its implications for society; and communication of those results to the scientific community, the public, and policymakers. Founded by J. Craig Venter, Ph.D., JCVI is home to approximately 120 scientists and staff with expertise in synthetic biology, human and evolutionary biology, genetics, bioinformatics/informatics, information technology, high-throughput DNA sequencing, genomic and environmental policy research, and public education in science and science policy. JCVI is a 501(c)(3) organization. For additional information, please visit www.jcvi.org.

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