The search for novel enzymes capable of biodegrading polystyrene, polyethylene, and polyvinyl chloride

Petroleum-based plastics are recalcitrant and pervasive environmental contaminants. Recycling only recovers 9% of post-consumer plastic, the rest is landfilled, incinerated, or discharged into the environment. While most plastic recycling methods convert plastic into lower value products, biocatalytic plastic depolymerization to component monomers then available for resynthesis of valuable products is an attractive alternative. Biocatalyst-based recycling is already used to recycle polyethylene terephthalate (PET). However, we do not have promising enzyme candidates for recycling for the most abundant plastics: polyethylene, polystyrene, and polyvinyl chloride which collectively account for ~45% of plastic waste produced annually. The homoatomic C-C backbone of these polymers renders them more resistant to degradation than the heteroatomic backbone of plastics like PET. Enzymes capable of oxidatively cleaving C-C bonds are of particular interest in development of biocatalyst-based recycling of these plastics. Laccases are a key enzyme family that cleave C-C bonds and that have the potential to impact C-C backbone plastics. The overarching goal of the Mitacs Globalink research project is to identify novel laccases by synthesizing and screening functional metagenomic libraries from diverse environments, and preparing these novel laccases identified for expression and purification to assess their suitability as biocatalysts for industrial recycling of C-C backbone plastics.

Faculty Supervisor:

Elizabeth Edwards;Laura Hug

Student:

Partner:

Universität Hamburg

Discipline:

Engineering

Sector:

Education

University:

University of Toronto

Program: