Degradable Living Plastics Programmed by Engineered Microbial Consortia

Abstract

Plastics are extensively used, yet their resistance to degradation has led to severe environmental and ecological concerns. Recent advances in synthetic biology have enabled the development of spore-embedded living plastics. Living plastics can function when the spores are dormant and decay when the spores are activated. However, the degradation efficiency of individual Bacillus strain and the single-enzyme system remains limited. To address this challenge, we engineered a consortia-embedded living plastic. Bacillus subtilis are separately programmed with an inducible gene circuit capable of secreting two complementary plastic-degrading enzymes: Candida antarctica lipase, responsible for random-chain scission, and Burkholderia cepacia lipase, responsible for processive depolymerization and is stressed to sporulation. Embedding these two-spore communities into the polymer matrix does not compromise the material’s mechanical properties. Spore activation is achieved through controlled heating. The cooperative enzymatic activity within the microbial consortia outperforms that of a single-strain system, enabling near-complete degradation of the polycaprolactone (PCL) matrix within 6 days. We have further fabricated flexible, degradable electronic devices capable of detecting human electromyography signals using the consortia-based living plastics. Our method offers a potential strategy for tackling plastic pollution through programmed coordinated biological systems.