Investigation of novel polyester-degrading cutinases for the depolymerization of plastic in mixed waste streamsAuthors: Chloé Allo, Doris Ribitsch, Georg Gübitz Presented at Carbios 2nd International Conference, 8-10 October 2024, Toulouse. The MixMatters project develops an Integrated System to separate and valorise mixed waste streams from the agri-food sector, where plastic contamination poses a significant challenge for conventional recycling. This study focuses on using enzyme-based depolymerization to enable the selective recovery of plastic monomers from these complex waste fractions. Two novel polyester-degrading cutinases (Abc and Scc), identified from soil and wastewater metagenomes, were successfully expressed in Escherichia coli and tested for their ability to hydrolyse polyethylene terephthalate (PET)—a common plastic in food packaging. Their enzymatic activity under different environmental conditions is being evaluated to assess their potential for industrial-scale waste valorisation. These enzymes will be further tested on waste streams from MixMatters, aiming to integrate biotechnological plastic recycling into a sustainable circular economy approach.