Capture and degradation of micro-plastics by a synthetic biology approach to engineer novel PET-degrading enzyme linked amyloid nano-material

Accumulation of microplastic waste in the environment is a costly and ongoing societal challenge that can potentially be addressed through the recent discovery of enzymes that are able to degrade Polyethylene terephthalate (PET) and recycle it into its constituent building blocks. However, no efficient materials applications currently exist that utilise these enzymes. This project will use a synthetic biology approach to engineer a novel biomaterial based on linking PET degrading enzymes onto functional amyloid fibrils formed from the yeast protein Sup35NM as scaffold. Amyloid fibrils are a type of protein structures with a characteristic fibrous shape. Some amyloid fibrils are well-known to be associated with diseases such as Alzheimer's disease, Parkinson's disease, and systemic amyloidosis. However, many amyloid structures are beneficial, or "functional" in that they fill essential biological roles, for example the functional amyloid protein Sup35 from Baker's yeast. Sup35 forms amyloid fibrils in yeast cells and this allows it to functions normally as a molecular switch. Importantly, Sup35 has three parts and only two of these are required to make the amyloid fibrils, these two parts are known as Sup35NM. We intend to replace the 3rd part with enzymes such as PETase which could functionalise the Sup35NM amyloid fibrils and imbue them with PET degrading functionality. Collaborative work in the Xue and von der Haar labs has already generated the first Sup35NM-PETase WT fusion protein, demonstrating the feasibility and the training potential of this project. In this project, the successful PhD candidate will generate new fusion proteins containing recently discovered PETase sequences with mutations that enhance their activity. They will then assemble synthetic filaments as well as meshes, and characterise the structure and the PET degrading activity of the materials made.