Directed Evolution of Material Binding Peptide for Polylactic Acid-specific Degradation in Mixed Plastic Wastes

ACS Catalysis, vol. 13, pp. 12746–12754

Abstract

In order to preserve our livelihood for future generations, responsible use of plastics in a climate-neutral and circular economy has to be developed so that plastics can be used in an environmentally friendly way by future generations. The prerequisite is that bioplastic polymers such as polylactic acid (PLA) can be efficiently recycled from petrochemical based plastic. Here, a concept in which accelerated PLA degradation in the mixed suspension of PLA and polystyrene (PS) nanoparticles has been achieved through an engineered material binding peptide. After comparison of twenty material binding peptides, Cg-Def is selected due to its PLA binding specificity. Finally, a suitable high-throughput screening system is developed for enhancing material-specific binding toward PLA in presence of PS. Through KnowVolution campaign, a variant Cg-Def YH (L9Y/S19H) with 2.0-fold improved PLA binding specificity compared to PS is generated. Contact angle and surface plasmon resonance measurements validated higher surface coverage of Cg-Def YH on PLA surface and the fusion of Cg-Def YH with PLA degrading enzyme confirmed the accelerated PLA depolymerization (two times higher than only enzyme) in mixed PLA/PS plastics.

Authors 5

1. Yi Lu Aachen Institute of Biotechnology

   RWTH Aachen University

   Affiliation as printed

   Institute of Biotechnology, RWTH Aachen University, Aachen 52074, Germany

2. Kai‐Wolfgang Hintzen Aachen DWI - Leibniz Institute for Interactive Materials Institute of Biotechnology

   DWI – Leibniz Institute for Interactive Materials · RWTH Aachen University

   Affiliation as printed

   DWI-Leibniz Institute for Interactive Materials, Aachen 52074, Germany

   Institute of Biotechnology, RWTH Aachen University, Aachen 52074, Germany

3. Tetiana Kurkina Aachen Institute of Biotechnology

   RWTH Aachen University

   Affiliation as printed

   Institute of Biotechnology, RWTH Aachen University, Aachen 52074, Germany

4. Yu Ji corresponding Aachen Institute of Biotechnology

   RWTH Aachen University

   Affiliation as printed

   Institute of Biotechnology, RWTH Aachen University, Aachen 52074, Germany

5. Ulrich Schwaneberg corresponding Aachen DWI - Leibniz Institute for Interactive Materials Institute of Biotechnology

   DWI – Leibniz Institute for Interactive Materials · RWTH Aachen University

   Affiliation as printed

   DWI-Leibniz Institute for Interactive Materials, Aachen 52074, Germany

   Institute of Biotechnology, RWTH Aachen University, Aachen 52074, Germany