Bioengineered Microorganisms: A New Solution for Plastic Waste Breakdown

According to the Environmental Protection Agency, the United States generates approximately 40 million tons of plastic waste annually, with polyethylene terephthalate (PET) accounting for 64%. As a common packaging plastic, PET is highly resistant to decomposition, taking centuries to break down. To address this issue, the Rice team created adhesive bacteria by incorporating a natural amino acid called 3,4-dihydroxyphenylalanine (DOPA), which is key to mussels' strong adhesion properties.

"Our research holds great potential for tackling the growing problem of plastic pollution in the U.S. and around the world," said study leader Han Xiao, Director of Rice's Synthesis X Center and an associate professor of chemistry, biosciences, and bioengineering.

Enhanced Adhesion for Plastic Degradation

Using genetic code expansion technology, the team successfully incorporated DOPA into bacteria, significantly boosting their ability to bind to PET surfaces. Tested at 37 degrees Celsius, the engineered bacteria displayed a remarkable 400-fold increase in adhesion. This enhanced adhesion was combined with a powerful enzyme known as polyethylene terephthalate hydrolase, which breaks down PET into smaller, more manageable fragments. The results showed significant plastic degradation within just one night.

A New Pathway for Efficient Recycling

The researchers' innovative approach offers a faster and more efficient method for breaking down plastic waste, presenting a new pathway for recycling and reducing environmental impact. "Our method underscores the innovative utility of genetic code expansion in material and cellular engineering. It holds great promise for solving real-world problems," said Xiao.

Combating Biofouling in Marine and Medical Applications

Beyond plastic degradation, the adhesive properties of the modified proteins have potential applications in addressing biofouling—the unwanted accumulation of microorganisms and algae on submerged surfaces. This phenomenon can damage ships, underwater structures, and pipes, resulting in costly maintenance. The DOPA-modified proteins can form a strong barrier on organic and metallic surfaces, effectively preventing biofouling.

In the healthcare sector, these interactions can be leveraged to create smart material-protein conjugates for various biomedical applications. "This research opens new avenues for developing advanced biomaterials for implantable medical devices, tissue engineering, and drug delivery,"added Mengxi Zhang, first author of the study and a graduate student in chemistry.

The Rice University team's groundbreaking work offers a multifaceted solution to the dual challenges of plastic waste and biofouling, paving the way for broader applications in environmental and medical fields.