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Researchers embedded an engineered common soil bacterium (Bacillus subtilis) inside a new plastic and programmed it to secrete two cooperating enzymes that fully break the polymer down in roughly six days once a trigger flips the dormant microbes
A new material reported in ACS Applied Polymer Materials embeds engineered Bacillus subtilis, a common soil bacterium, and fully breaks down in roughly six days under controlled activation, leaving no microplastics behind. The work, led by corresponding author Zhuojun Dai with co-authors Jin Geng and Dianpeng Qi at the Harbin Institute of Technology, sits inside a research program on "living plastics": polymer materials seeded with microbes that stay dormant until a trigger flips them into degradation mode.
The two-enzyme cooperation is the actual design move. The embedded Bacillus subtilis is engineered to secrete two polymer-degrading enzymes at once. One is an endo-type enzyme that cleaves long polymer chains at random internal points; the other is an exo-type enzyme that works inward from the chain ends. Earlier living-plastic designs relied on a single enzyme, and that bottleneck is what the new consortium design is meant to remove. The result, per the authors, is a more complete breakdown. Instead of leaving short polymer fragments that microplastics are made of, the two enzymes together chew the chains down through their full length.
Hiding polymer-degrading microbes inside a material turns durability itself into a programmable feature, and the ACS Press Pacs framing treats the consortium as a refinement on that concept rather than a new category. The category has been around for a few years under different names.
The six-day number is real, but it is also tightly bounded. The authors report it under controlled activation conditions; the press release and the Technology Networks coverage both restate that figure without characterizing ambient-soil, marine, landfill, or UV-exposed performance. None of the surfaced material characterizes mechanical strength, the shelf stability of dormant spores, the regulatory pathway, or scale-up economics. The six-day number alone does not answer whether this material can carry a load, survive a warehouse, or clear a regulator.
This is a step inside a research program, not a consumer-ready replacement. Author publication records at Harbin Institute of Technology show the team is treating the work that way. The next milestones that matter are not faster enzymes. They are real-environment breakdown curves, mechanical strength data, and a credible answer to whether dormant spores survive a real product's shelf life.