The environmental impact of current production and consumption practices of single-use plastics has prompted the development of new materials with a closed-loop life cycle. Of special mention are bioplastics that are at the same time biodegradable, compostable, or chemically recyclable. Recently, the synthesis of polyesters and polycarbonates with similar properties to polyethylene has been described, using C18 fatty acids of plant origin as feedstock. These polymers are chemically recyclable, allowing the efficient recovery of their constituent monomers for their re-polymerization. The bacterium Acinetobacter baylyi ADP1 naturally accumulates C16-C18 fatty acids as wax esters, which have been considered for many years as sustainable alternatives to wax esters of plant and animal origin. Additionally, its genetic malleability has allowed the implementation of numerous metabolic engineering tools. In this project, we propose to apply synthetic and systems biology tools in A. baylyi for the production of wax esters or their precursors from extant plastic wastes, with the goal of obtaining bio-derived monomers for the synthesis of new, chemically recyclable plastics. To this end, we will modify native metabolic pathways and introduce heterologous pathways to direct the carbon flux from plastic waste-derived monomers towards the synthesis of wax esters. Additionally, we will explore the potential of A. baylyi to form biofilms on plastic surfaces and secrete depolymerizing enzymes. In all, the proposed work will pave the way towards the production of sustainable bioplastics that will contribute to establishing a circular economy.

This project is funded through an agreement between the CSIC and the Reina Sofía Foundation, with the collaboration of the Primafrío Foundation. The goal of this agreement is to attract young scientists to lead a new research line in the context of the Interdisciplinary Thematic Platform for Sustainable Plastics towards a Circular Economy (PTI+ SusPlast).