Potential plastic biodegradation in lakes worldwide

Public summary

* Plastic waste contributes to the geographical distribution of global lake plastic-degrading potential.

* We develop a computational framework to assess environmental application potential of plastic degraders.

* Most plastic-degrading bacteria lack complete essential growth factor pathways.

* We provide a proof-of-concept framework to identify and harness novel plastic degraders.

Abstract

Plastic pollution is ubiquitous, yet the biodegradation of plastic waste remains poorly understood due to limited knowledge of microbial plastic degradation potential. Here, we demonstrate that plastic waste shapes the global distribution of plastic-degrading potential across 182,661 lakes worldwide using integrated metagenomic and machine learning analyses and identify a tipping point (≥7.44 particles/m3) for effective in situ bioremediation. We constructed, for the first time, a catalog of candidate plastic-degrading bacteria, including 15,715 nonredundant enzyme homologs and 4,856 metagenome-assembled genomes. To facilitate future applications, we developed a computational approach to categorizing candidate plastic-degrading bacteria according to their degradation potential, ecological risk, environmental adaptation, and competition capacity. Furthermore, we customized eight template culture media based on the growth factor biosynthesis profiles of high-priority candidate plastic-degrading bacteria. Using these media, we successfully enriched the plastic-degrading microbial communities and isolated a high-priority strain, Serratia ficaria HfyG-1, from Xiazhu Lake, which harbors a wide variety of previously uncharacterized putative degrading enzymes that effectively degrade polylactic acid and polyethylene terephthalate. Our study provides a molecular resource for the bioremediation of plastic-polluted environments worldwide and highlights a proof-of-concept framework for identifying, investigating, and exploiting unknown functional microorganisms for practical applications.