Engineered and Robust Biocatalysts for Plastic Waste Upcycling: From Depolymerization to Value-Added Biopolymers

Plastic waste accumulation is one of the defining environmental problems of our time, and the biological route to managing it is increasingly favoured because it is milder, safer, and more selective than energy-intensive chemical or thermal processes. Yet biology faces two coupled bottlenecks. First, synthetic polymers are recalcitrant and require robust, stable, and efficient enzymes and microbes to be broken down. Second, the products of that breakdown are only worth capturing if they can be redirected into materials of real value. Enzymes and microorganisms from diverse sources, including those from extreme environments, combined with recombinant expression and protein engineering, offer the thermostability, tolerance, and broadened substrate range needed for industrially relevant conversion. On the product side, microbial platforms already convert renewable and waste-derived carbon into value-added biopolymers such as polyhydroxyalkanoates and exopolysaccharides.GoalThis Research Topic reframes plastic waste not as an endpoint but as a feedstock, connecting robust biocatalysts for depolymerization on the front end with microbial synthesis of value-added biopolymers on the back end, into circular, bio-based routes. We aim to bring together fundamental and applied work that advances the discovery, engineering, and application of enzymes and microbes for plastic-waste upcycling, and that demonstrates how the resulting carbon can be captured as functional biopolymers and bio-based materials. We particularly welcome studies on bioprospecting and engineering of thermostable and solvent-tolerant biocatalysts; microbial and mixed-culture bioconversion of plastics; and the conversion of depolymerization products and renewable waste substrates into polyhydroxyalkanoates, exopolysaccharides, and related biopolymers. By linking depolymerization and biopolymer production, the collection seeks to consolidate a coherent, biocatalyst-centred vision of the plastic-to-biopolymer value chain within industrial biotechnology.Scope and information for authorsWe invite Original Research, Reviews, and other article types on: (1) discovery and engineering of robust biocatalysts for plastic depolymerization — bioprospecting, recombinant expression of thermostable enzymes, protein engineering, and enzyme cocktails acting on a broad range of synthetic and bio-based polymers;(2) microbial and mixed-culture bioconversion of plastic waste, including pretreatment and adaptive strain selection;(3) upcycling of plastic-derived and renewable waste carbon into value-added biopolymers such as PHA and EPS;(4) biocatalytic functionalization and integrated processing for circular polymer routes; and(5) genomic, metagenomic, and systems-level insights into plastic-degrading and biopolymer-producing microbes.Out of scope: purely chemical or thermal recycling; environmental monitoring or ecotoxicology of micro-/nano-plastics without a biocatalytic focus; standalone techno-economic or life-cycle assessments; and purely computational enzyme design without experimental validation. Topic editors: Tajalli Keshavarz, Rajesh K Sani Source: https://www.frontiersin.org/research-topics/83997/engineered-and-robust-biocatalysts-for-plastic-waste-upcycling-from-depolymerization-to-value-added-biopolymers