Development of functional living materials for plastic degradation

Abstract

Engineered living materials (ELMs) are gaining traction among synthetic biologists. Thanks to their unique capabilities of growth, self-regeneration, genetic programmability, and sustainability, the ELMs provide enormous opportunities for addressing environmental and health-related challenges. In this thesis, we aim to demonstrate the feasibility of using engineered living cells as building blocks, alongside ultra-high-affinity protein/protein interactions, to construct ELMs, the latter of which can be further genetically programmed for plastic degradation, a long-standing challenge facing environmental remediation. To create the plastic-degrading ELMs, we genetically engineered two types of eukaryotic microorganisms, i.e., the heterotrophic species Saccharomyces cerevisiae (Baker’s yeast) and the photosynthetic diatom Thalassiosira pseudonana; the resulting strains were able to produce and display two functional motifs, including the enzyme PETase for the degradation of polyethylene terephthalate (PET), a widely used plastic, and the peptide/protein pair SpyTag/SpyCatcher for the covalent assembly of cells. These engineered cells demonstrated the ability not only to assemble into stable multicellular conjugates but also to degrade PET over extended periods. The successful application of ELMs in plastic degradation underscores the broader applicability of this platform, paving the way for applications in various other fields. By leveraging the genetic programmability of microorganisms, this platform can be further expanded to target a broader range of substrates, accommodating diverse applications such as environmental remediation, biosensing, and the production of valuable biochemicals.

Date of Award	2024
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology
Supervisor	Fei SUN (Supervisor)