About This Project

Microplastics (MPs) are widely dispersed in nature and negatively impact the biosphere. Unlike larger plastic waste, MPs are too small to mechanically remove from the environment with nets or other methods. Protein-based plastic binding domains have the potential to efficiently detect and capture MPs from the environment. Since MP waste is extremely diverse (10 or more distinct types of MPs), we propose a yeast display engineering platform to establish diverse capture agents.

Ask the Scientists

What is the context of this research?

Microplastics (MPs) are small plastic particles that have been dispersed throughout the planet by human activities (MPs are defined here as any plastic between 1 nm and 10 mm in diameter). Millions of tons of MPs estimated to exist in nature. Unlike macroscopic plastics, MPs cannot be efficiently removed from the environments using nets or other established mechanical separation processes. In addition, there are easily 10 or more distinct types of MP contaminants, whose distribution, type, and amount varies dramatically as a function of environmental location.

What is the significance of this project?

Substantial research efforts are underway to engineer plastic-degrading enzymes, which can be used to digest MPs. However, the diversity and wide range of MP properties make it difficult to effectively deploy enzymes without concentrating MPs and identifying the type(s) of MP waste present in a sample. MPs are derived from 5 or more distinct plastics and can be modified physically, chemically, or biologically once dispersed in the environment. All of these challenges motivate the need to engineer plastic binding domains capable of capturing MPs with diverse properties. Such binding domains would facilitate identification of the presence of microplastics in a sample and capture and sequestration of the microplastics to facilitate more efficient degradation of the plastics.

What are the goals of the project?

This project seeks to establish a powerful platform for the discovery and engineering of plastic binding domains. Implementing a new engineering platform is a high-risk, “0-to-1” type project, but the successful completion of the proposed milestones will establish foundational technology for MP remediation. Our specific goals are to 1) demonstrate that yeast display supports MP binding, with flow cytometry assay signals at least 3-fold higher than background signals; 2) establish parallel evaluation of candidate plastic binding domains with a demonstrated throughput of 100 or more samples/day; 3) demonstrate that we can evolve plastic binding domains to recognize MPs with greater than 5-fold improved affinity.