Mussels inspire sticky way to clean up plastic waste

Scientists have tapped into nature’s adhesive genius—the sticky power of mussels—to create bioengineered microorganisms with powerful cling that could help transform environmental cleanup.

By combining this amplified sticking force with an enzyme that breaks down harmful plastics, their discovery offers a potential new tool for tackling plastic pollution.

The research in Small Methods could also curb biofouling, addressing long-standing challenges in industries ranging from shipping to medicine.

The US produces about 40 million tons of plastic waste annually, according to the Environmental Protection Agency, with polyethylene terephthalate (PET) accounting for 64%. PET, a plastic often found in packaging, is notoriously resistant to degradation, taking centuries to decompose.

The team’s innovation allowed it to create adhesive bacteria and proteins that could help countries worldwide more efficiently decompose PET.

“Very excitingly, our research holds promise for addressing the growing problem of plastic pollution in the US and across the globe,” says study leader Han Xiao, the director of Rice University’s Synthesis X Center; an associate professor of chemistry, biosciences, and bioengineering; and a Cancer Prevention and Research Institute of Texas (CPRIT) scholar.

The engineered bacteria were designed using genetic code expansion technology, incorporating a natural amino acid called 3,4-dihydroxyphenylalanine (DOPA), responsible for mussels’ adhesive properties. The researchers significantly enhanced their ability to bind to PET surfaces by modifying the bacteria with DOPA.

The altered bacteria, tested on PET samples at 37 degrees Celsius (98.6 degrees Fahrenheit), demonstrated a 400-fold increase in adhesion. This cohesive bacteria was united with an enzyme called polyethylene terephthalate hydrolase to break the material into smaller, more manageable fragments, resulting in what the researchers call a significant amount of degradation of the plastics overnight.

This innovative approach could provide a novel solution to plastic recycling, offering a faster and more efficient way to reduce plastic waste and its environmental impact.

“Our approach underscores the innovative utility of genetic code expansion in material and cellular engineering. It can potentially transform bioengineering applications and solve real-world problems,” Xiao says.

In addition to addressing plastic pollution, the research offers potential solutions to biofouling, the unwanted accumulation of microorganisms, plants, algae, and small animals on submerged surfaces that can damage ships’ hulls, underwater structures, and pipes.

The DOPA-modified proteins showed strong bonding capabilities to organic and metallic surfaces, creating a barrier that prevents the accumulation of microorganisms and other materials.

Moreover, the researcher’s discovery has broad applications, including the health care field. For example, it can be used to prevent bacterial growth on medical devices, making them safer and more effective, the researchers say.

“This will open up new avenues for leveraging these interactions to develop smart material-protein conjugates for various biomedical applications like implantable medical devices, tissue engineering, and drug delivery,” says Mengxi Zhang, first author of the study and a graduate student in chemistry.

Grants from CPRIT, the National Institutes of Health, the Robert A. Welch Foundation, the US Department of Defense, the John S. Dunn Foundation Collaborative Research Award, and the Hamill Innovation Award supported this research.

Source: Rice University