MIXed plastics biodegradation and UPcycling using microbial communities

ended

The continuing demand for plastic products, the lack of appropriate recycling and the ubiquitous pollution of the environment with plastic waste pose a global challenge. An ambitious vision and considerable efforts are required to change the traditional value chain of plastics to a sustainable one, based on biodegradable plastics. In MIX-UP, plastic mixtures with five of the top six fossil-based recalcitrant plastics (PP, PE, PUR, PET, and PS), along with upcoming biodegradable plastics such as PLA and PHA, will be used as feedstock for microbial transformations, thereby generating a workflow that increases the recycling quota and adds value to poorly recycled plastics waste streams. Successive controlled enzymatic and microbial degradation of mechanically pre-treated plastics waste will be combined with subsequent microbial conversion to value-added chemicals and polymers by mixed cultures. We will optimize known plastics-degrading enzymes for high specific binding capacities, stability, and catalytic efficacy towards a broad spectrum of plastics polymers under high salt and temperature conditions by integrated protein engineering, and also isolate novel enzymes with activities on recalcitrant polymers. MIX-UP will also optimize the production of enzymes and formulate enzyme cocktails tailored to specific waste streams. Implementation of these enzymes, both in vitro and in vivo, enables stable self-sustaining microbiomes to convert the released plastic monomers selectively into at least six value-added products, key building blocks, and biomass. Any remaining material recalcitrant to enzymatic activity will be recirculated into the process after a physico-chemical treatment. The Chinese-European MIX-UP is a multidisciplinary and industry-driven consortium that addresses the market need for novel sustainable routes to valorise plastics waste streams. MIX-UP realises a circular (bio)-economy and could be a viable alternative for mechanical and chemical recycling.