Towards the biological degradation of plastics: Genetic engineering of Saccharomyces cerevisiae to secrete Ideonella sakaiensis derived PETase.

In this project we demonstrated that two strains of Saccharomyces cerevisiae, were able to produce the heterologous protein Polyethylene Terephthalate (PET) hydrolase from the novel bacterium Ideonella sakaiensis. This novel enzyme has

been shown to have the capability of degrading PET into its subsequent monomers, Ethylene Glycol and Terephthalic acid. The original native form of PET hydrolase was mutated by the Beckham lab (Skaf et al. 2018) to increase efficiency of degradation, the two residues changed were at the active site which resulted in the narrowing of the cleft. The residues changed were Tryptophan at position 159 to a Histidine residue; and Serine at position 238 to a Phenylalanine. In this study the double mutant form of the enzyme was used. In this project we also demonstrated the capability of PETase expressed by Saccharomyces cerevisiae to cause surface changes on waste PET samples. Lastly, we have also shown that Saccharomyces cerevisiae has the ability to form cell clusters similar to biofilms on a PET surface. All of these findings point to the viability of using Saccharomyces cerevisiae as a novel system for plastic waste removal in an industrial setting.