Bioengineered Bacterial Spores Found for Broader New Applications

A quiet revolution is unfolding in bacterial spore engineering, where nature’s toughest survival strategy is being repurposed for next-generation biotech. Spores, produced when bacteria face extreme heat, cold, dehydration, nutrient loss, or disinfectants, can remain dormant for years or even centuries. Inside each hardened, protein-coated sphere lies DNA protected against harsh conditions until conditions improve and the spore germinates.

That stability has made spores attractive as biological “platforms” for delivering functional molecules without refrigeration. By fusing useful proteins to the outer coat, researchers can create tailored catalysts, enzymes, sensors, and even vaccine components that tolerate heat and chemical stress far better than many conventional biologics.

Until now, progress has been constrained by a major bottleneck: only a small fraction of the ~50 proteins that form the spore coat had been explored as fusion candidates. With fewer targets, researchers couldn’t systematically optimize performance or expand the range of deployable products.

Now, Tufts chemical and biological engineering researcher Nik Nair and his team have broadened the search dramatically, identifying as many as 33 coat proteins as viable fusion targets. Published in JACS Au, the study uses an extensive survey approach to reveal which spore surface components best support functional display, enabling a much larger design space for bioengineered applications.

The team’s results highlight a key technical insight—accessibility and stability matter. For polyethylene terephthalate (PET) recycling, they fused spore coat proteins with enzymes that break PET into monomers. The small coat assembly protein SscA delivered especially strong performance in controlled tests, showing a fourfold activity advantage over other fusions in their comparison set.

However, when shifting from model substrates to real solid PET, the outer coat protein CotY outperformed others, aligning with its more exposed positioning on the spore surface. This distinction underscores how microanatomy governs real-world catalytic efficiency, not just lab-scale behavior.

Beyond single-step reactions, the work suggests a route toward multi-stage plastic degradation—first dissolving solid polymers, then converting released chemicals into more environmentally benign products via additional engineered steps.

Safety remains the critical next question for real-world deployment. Because spores can potentially reactivate, the researchers emphasize strategies to block germination by deleting specific genes, ensuring engineered spores remain inert and stable after release.

Finally, the technology is moving beyond the lab. A new startup, Caravel Bio, is being spun out from the research to advance applications ranging from oral vaccine delivery to chemical detection and PET breakdown in harsh environments.

Keywords

Spores, bioengineering, protein display, biofuels, environmental remediation, PET recycling, catalytic enzymes, bacterial dormancy