Aromatic compounds, such as dioxins and benzene, are major soil pollutants. Their high chemical stability makes them resistant to microbial and chemical degradation, leading to toxic accumulation in the soil.

Previous studies have used genetic engineering to enhance the capacity of microorganisms to degrade environmental pollutants. However, strict ecological regulations restrict the use of genetically engineered microorganisms (GEMs) in natural environments.

In a study published in the , ºÚÁϳԹÏÍø researchers demonstrated that native soil bacteria, when treated with decoy molecules, can degrade non-native compounds, including persistent pollutants such as dioxins, without genetic modification.

“In other words, we can effectively give these bacteria capabilities they do not naturally have, while keeping them in their original state,” said Professor , the study’s lead author.

Shoji and doctoral students Fumiya Ito and Masayuki Karasawa at investigated the application of cytochrome P450, a widely distributed group of enzymes that degrade and convert substances in living organisms.

Cytochrome P450BM3, derived from the soil bacterium Priestia megaterium, naturally hydroxylates fatty acids but does not interact with pollutants such as dioxins. This substrate selectivity arises from the lock-and-key mechanism, which allows only molecules with a specific shape to bind to the enzyme.

While the GEM approach introduces mutations to alter enzyme binding sites for target molecules, the team instead used decoy molecules that mimic fatty acids to induce the enzyme to degrade pollutants.

“In our previous research, we successfully induced otherwise unlikely reactions by deceiving enzymes with decoy molecules,” said Shoji.

Decoy molecules bind to enzymes in a manner similar to fatty acids; however, their shorter chain length prevents them from reaching the active site. This configuration creates a confined reaction space that allows molecules to enter and undergo hydroxylation. Because decoy molecules are not themselves hydroxylated, they maintain their function and continue to facilitate the enzymatic reaction.

Assessment of decoy molecules in soil bacteria

Researchers evaluated the biochemical responses of 10 bacterial strains, each harboring cytochrome P450BM3 or closely related enzymes, using a set of 76 decoy molecules.

The results showed that benzene hydroxylation occurred only with particular strain-decoy combinations. The tested strains included P. megaterium, which contains cytochrome P450BM3, as well as other common soil bacteria, such as Bacillus subtilis, which possess closely related enzymes.

Gene-knockout experiments further confirmed the involvement of cytochrome P450 in these bacteria.

These bacteria also successfully hydroxylated other aromatic compounds, including toluene, xylene and naphthalene.

Surprisingly, in the presence of decoy molecules, B. subtilis completely degraded dioxin model compounds within two hours at 45 degrees Celsius. Computational simulations demonstrated that cytochrome P450 in B. subtilis has sufficient binding capacity to accommodate both a decoy molecule and dioxin, which is a larger pollutant than benzene.

The findings indicate that the decoy molecule-induced hydroxylation activity in these bacteria increases the solubility of pollutants and facilitates their degradation. This mechanism could accelerate the removal of soil pollutants by supporting faster and more efficient microbial degradation.

Conclusion and future perspectives

Systematic screening of diverse soil bacteria, combined with various decoy molecules, enabled the identification of highly active combinations. Notably, multiple bacterial species responded to these molecules, suggesting that this approach could be broadly applicable rather than limited to a specific organism.

Shoji concluded, “Our study provides a generalizable chemical strategy to unlock latent catalytic potential in ubiquitous environmental microbes, establishing a new paradigm for scalable, regulation-compatible bioremediation technologies.”

Paper information:

Fumiya Ito, Masayuki Karasawa, and Osami Shoji (2026). Chemical activation of native cytochrome P450s in soil-derived bacteria by external molecules enables biodegradation of aromatic pollutants, Journal of Materials Chemistry A. DOI:

Expert contact:

Osami Shoji
Graduate School of Science, ºÚÁϳԹÏÍø
Email: shoji.osami.w3@f.mail.nagoya-u.ac.jp

Media contact:

Naomi Inoue
International Communications Office, ºÚÁϳԹÏÍø
Email: icomm_research@t.mail.nagoya-u.ac.jp

Top image:

Non-genetic cleanup of environmental pollutants using native soil bacteria
By introducing “decoy molecules,” scientists can trick the bacteria’s natural enzymes into breaking down stubborn, toxic chemicals like benzene and dioxins.
(Credit: Osami Shoji)

Study finds that multisensory museum experiences help shift public perception of endangered cultural heritage

What does it take to make people genuinely care about endangered cultural heritage? According to a new study from researchers at ºÚÁϳԹÏÍø and Gifu University in Japan, the answer might begin with something unexpected: the smell of horse manure. Their research, published in the Journal of Museum Education, found that structured multisensory experiences can shift public perception of heritage from something distant and extraordinary to something personally relevant.

Museums have long struggled to translate public recognition of cultural heritage into genuine engagement. Visitors may appreciate that something is historically significant, yet still feel little personal connection to it. Using Japan’s native Kiso horse as a case study, the researchers found that this gap is real and measurable. Survey analysis showed that visitors widely recognized the horse as a valuable cultural resource, but tended to perceive it as part of an “extraordinary” world, separate from their everyday lives.

To address this, they developed the Sense-Science-Significance (S-S-S) model, an educational framework that guides visitors from direct sensory experience through analytical understanding to reflection on cultural and ecological value. “We want visitors to feel that heritage belongs to their world, not just to an exhibition case,” said lead author Ayako Umemura, a designated assistant professor at ºÚÁϳԹÏÍø Museum.

The Kiso horse: a breed nearly lost

The Kiso horse is one of Japan’s eight surviving native horse breeds, originating from the mountainous Kiso region of present-day Nagano and Gifu Prefectures. Compact and sure-footed, it was historically used for agricultural work and transport. In the twentieth century, the breed came close to extinction following a government policy to castrate native stallions in favor of larger horses suited for military use. The breed survived through Dai-san Haruyama, a purebred stallion who sired around 700 foals and whose skeleton is now preserved at ºÚÁϳԹÏÍø Museum.

A problem of perception

The research began with a 2022-2023 special exhibition at ºÚÁϳԹÏÍø Museum built around the skeletal specimen of Dai-san Haruyama. Text analysis of 88 visitor survey responses confirmed the core problem: despite recognizing the Kiso horse as culturally important, visitors rarely connected that recognition to their own lives or to a sense of personal responsibility for conservation. Visitors’ impressions of the horse remained largely surface-level and did not readily translate into deeper engagement. The researchers used these findings to design a second, more deliberately structured exhibition and to formalize the S-S-S model as a replicable framework.

Engaging the senses

In a second exhibition held in 2024 at Kiso Town Cultural Exchange Center, the researchers put the S-S-S model into practice. Rather than relying on panels and displays alone, the exhibition asked visitors to engage their senses directly. They could handle and compare hoof models from a Kiso horse and a Thoroughbred, with one visitor remarking that the Kiso horse hoof felt “plump and endearing”¡ªa small detail that opened into a larger conversation about how the breed’s compact build made it so well suited to mountain terrain. They smelled horse manure at two stages of fermentation, gaining a tangible sense of the realities of horse husbandry. They could also listen to archival recordings from a traditional Kiso horse market, capturing the atmosphere of a practice that has since disappeared.

Each experience was paired with scientific context designed to prompt comparative and analytical thinking about the horse’s biology, ecology, and history. Survey analysis of 75 participants showed that the approach worked. Visitors frequently reflected on functional and ecological aspects of horse care they had not previously considered, and when asked what they would like to convey to others about the Kiso horse, 72% provided concrete, expressive answers.

A framework for broader application

The S-S-S model has since been applied in over 30 museum education events annually at ºÚÁϳԹÏÍø Museum, covering topics from physical specimens to broader environmental challenges and reaching audiences ranging from children to older adults.

The researchers argue that the challenges it addresses, including raising awareness, sustaining engagement, and linking conservation with education, are shared by museums around the world and across many types of cultural heritage. “The framework is not intended as a prescriptive solution, but as a flexible guide that educators can adapt to their own context,” said Umemura.

Publication

Ayako Umemura and Masaki Takasu. (2026). Sense-Science-Significance Model: A Museum Education Framework for Engaging Visitors with Cultural Heritage. Journal of Museum Education, 1¨C13.

Funding

This work was supported by a Grant-in-Aid for Scientific Research (JSPS KAKENHI) under JP23K02763.

Media contact

Alexander Evans
International Communications Office, ºÚÁϳԹÏÍø
icomm_research@t.mail.nagoya-u.ac.jp

Expert contact

Ayako Umemura
ºÚÁϳԹÏÍø Museum
umemura.ayako.v4@f.mail.nagoya-u.ac.jp

Top image

A group of Kiso horses graze in an open field on a clear day. Researchers found that museum visitors recognized the Kiso horse as culturally valuable, but rarely felt it had anything to do with their own lives. A new study from ºÚÁϳԹÏÍø and Gifu University set out to change that. Credit: Ayako Umemura, ºÚÁϳԹÏÍø Museum