The invention of plastics has greatly facilitated modern daily life. Yet the massive volume of plastic waste generated, combined with improper disposal practices, has made plastic pollution — commonly known as "white pollution" — one of the most pressing environmental challenges of our time. The core difficulty lies in the fact that petroleum-based plastics require hundreds of years to break down in nature, leaving a lasting toll on soil and ecosystems. To tackle white pollution at its source, biodegradable alternatives such as polylactic acid (PLA) have emerged as the leading solution.
To further accelerate degradation, Chinese scientists have developed an innovative "living" plastic.
A class of bio-derived polymers can be naturally broken down within a year by microorganisms and enzymes present in the environment. These materials — including polylactic acid (PLA), poly(butylene adipate-co-terephthalate) (PBAT), polyhydroxyalkanoate (PHA), poly(butylene succinate) (PBS), and polycaprolactone (PCL) — are collectively known as biodegradable plastics.
Their adoption is already widespread: paid biodegradable shopping bags in supermarkets, biodegradable straws in food service, and absorbable surgical sutures that eliminate the need for stitch removal.
Spores: The Key to Faster Degradation
Boosting degradation rates requires a higher concentration of degrading enzymes. Embedding these enzymes directly into the plastic allows for automatic release upon disposal. The challenge, however, is preserving enzyme activity during the product's usable life while triggering degradation only after it is discarded. Researchers found an elegant answer in a specialized bacterial structure: the spore.
Over billions of years of evolution, many microorganisms have developed remarkable resilience. When conditions become too extreme for growth and reproduction, bacteria enter a dormant spore state that grants extraordinary resistance to desiccation, heat, and pressure — precisely the harsh conditions encountered during plastic manufacturing.
Building on this, the team led by Dai Zhuojun at the Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, used synthetic biology to engineer Bacillus subtilis. They introduced a genetic circuit that enables controlled secretion of a plastic-degrading enzyme — Burkholderia cepacia lipase (Lipase BC) — and then induced the bacteria to form spores in a manganese-ion-rich environment.
The resulting spores retain the engineered genetic circuit while gaining tolerance to high temperature, high pressure, organic solvents, and dryness. The team mixed these engineered spores directly with PCL masterbatches and produced a series of spore-embedded plastics via melt extrusion or solvent casting.
Mechanical testing revealed no significant differences between the "living" plastic and conventional PCL in yield strength, ultimate stress, maximum deformation, or melting point. Crucially, in soil environments and without any external additives, the living plastic fully degraded within 25–30 days, compared with roughly 55 days for standard PCL to disappear from view.
To demonstrate the system's broad applicability, the researchers extended the approach to other polymer systems — including PBS, PBAT, PLA, PHA, and polyethylene terephthalate (PET) — successfully producing corresponding "living" plastic variants.
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