A Fungus That Survives Radioactive Radiation… but Not UV-C
In the Chernobyl exclusion zone, researchers discovered a surprising fungus: Cladosporium sphaerospermum. This microscopic organism, coated in melanin, has the ability to survive—and even thrive—in environments where radioactivity is lethal to most forms of life. As reported by Forbes, this black, melanin-rich fungus was observed on the walls of reactor No. 4, inside the Chernobyl sarcophagus, in a highly radioactive zone.
Unlike most life forms that succumb to ionizing radiation, this microorganism not only survives but grows faster in a radioactive environment. Its main peculiarity is that its melanin appears to absorb gamma rays to fuel its metabolism. Experiments conducted aboard the International Space Station (ISS) confirmed that this fungus can capture gamma radiation energy to stimulate its growth—a phenomenon nicknamed “radiosynthesis.”
This fascinating discovery opens perspectives in space radiation protection: the melanin of this fungus could one day help design anti-radiation shields to protect astronauts.
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Melanin: A Natural Shield Against Radiation
The exceptional resistance of Cladosporium sphaerospermum has intrigued researchers for years. In a landmark review published in 2008, Dadachova and Casadevall described how melanin acts as a true biological shield in many fungi exposed to radiation, citing C. sphaerospermum as an emblematic example.
According to their research, melanin absorbs the energy of ionizing radiation and reduces the formation of free radicals, thereby limiting cellular damage. It may even convert part of this energy into metabolic signals that stimulate growth—a mechanism known as radiosynthesis.
This protective role explains why these fungi resist highly radioactive environments, particularly gamma rays.
A Fascinating Phenomenon, But Not Invincible
In a dedicated article, Futura Sciences recalls that these melanized fungi demonstrate a rare ability: converting part of ionizing radiation energy into chemical energy usable by their cells. While remarkable, Futura stresses that this adaptation does not make the fungus invincible.
Indeed, UV-C at 254 nm directly targets DNA (pyrimidine dimers) and effectively neutralizes fungal spores. Available data indicate that a fluence of about 180 mJ/cm² achieves ≈ 2.5 log inactivation of Cladosporium under controlled conditions, leading to a recommended ≥ 250 mJ/cm² to achieve ≥ 3 log reduction on surfaces or in static air—adjusted depending on shading, sporulation state, and setup.
What Remains Uncertain (Even After 2022 Studies)
Despite experiments, notably aboard the ISS, several points remain unclear regarding the potential use of Cladosporium sphaerospermum in space radiation protection:
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The actual level of protection a biological shield made from this fungus could provide in space (duration, radiation type and intensity, variable conditions) is still not well defined.
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The long-term efficiency, stability, and how such a fungus or its melanin could realistically be integrated into astronaut protection systems remain at the experimental or hypothetical stage.
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Recent studies show mixed results: in some cases, radiation exposure changes pigmentation (melanin content) more than growth rate, suggesting the adaptation relies more on cell protection than true metabolic stimulation.
Why This Fungus Resists Gamma Rays but Not UV-C
Two to three hundred mJ/cm² of UV-C energy are enough to inactivate 99.9% of its spores—whereas gamma radiation fails to weaken it.
Gamma rays are highly energetic but diffuse in effect: they generate free radicals in cells, causing DNA breaks that C. sphaerospermum can repair, aided by its enhanced repair mechanisms and melanin, which traps these radicals and dissipates energy.
UV-C rays (254 nm), on the other hand, act very differently: they are directly absorbed by DNA, creating specific lesions (pyrimidine dimers) that this fungus cannot effectively repair.
Germicidal UV: Its Achilles’ Heel
Unlike gamma rays, UV-C (254 nm) emitted by low-pressure lamps penetrates cells directly and causes irreversible DNA damage. These lesions block replication, leading to rapid inactivation.
Even a fungus as resistant as Cladosporium sphaerospermum is neutralized within minutes by a germicidal dose delivered by our UV-C lamps at 254 nm, whereas gamma radiation only slows its growth.
From Science to Industry: Cladosporium Meets Its Limits with UV-C
Industrial integration example: on a packaging line, glass jars are decontaminated by UV-C irradiation before filling.
What research reveals in extreme environments like Chernobyl or space finds direct application in industry: the fungus’ resistance to gamma rays does not prevent it from being effectively neutralized by UV-C. This confirms both the efficacy and reliability of germicidal UV treatment solutions for the food, cosmetics, and pharmaceutical industries.
An Allergen and Industrial Contaminant
Even if Cladosporium sphaerospermum intrigues researchers for its potential in space biology, on Earth it remains a major undesirable contaminant in the food, cosmetics, and pharmaceutical sectors.
While fascinating for its resistance, this fungus is mainly known for spoiling stored fruits and vegetables. Rarely pathogenic to humans, it is nonetheless recognized as a respiratory allergen and may cause health issues in sensitive or immunocompromised individuals (rhinitis, asthma, subcutaneous phaeohyphomycosis, and isolated intrabronchial lesions).
Safeguarding the Food Chain with UV-C
In the food sector, contamination by Cladosporium or other molds poses not only indirect health risks but also significant economic losses: rejected batches, line stoppages, costly recalls. As our expertise shows, UV-C disinfection emerges as a robust, chemical-free technology to secure critical steps such as packaging treatment, conveyors, conditioning zones, as well as air and surface disinfection in production halls and laboratories.
Preserving the Quality of Natural Cosmetic Extracts
In the cosmetics industry, where purity of raw materials is essential, contamination is particularly problematic. Sensitive ingredients such as floral waters, fruit waters, plant extracts, or essential oils can lose all commercial value if affected. Cladosporium alters appearance (discoloration, deposits, turbidity) and can compromise regulatory compliance—even simply as an allergen.
UV-C light disinfection offers an ideal solution: it eliminates contaminants without chemicals or altering organoleptic properties, ensuring natural extracts remain compliant with bio and premium market expectations.
Ensuring Sterility in Pharmaceutical Environments
In the pharmaceutical industry, spores such as those of Cladosporium pose critical risks: even rare contamination can compromise sterility standards and batch compliance.
Here, UV-C systems integrate seamlessly into cleanrooms and isolators, disinfecting air, surfaces, and equipment to reduce cross-contamination. Already applied in many GMP (Good Manufacturing Practices) environments, UV-C reinforces biocontamination control and secures production of sensitive products such as vaccines, injectables, and sterile cosmetics.
Our Industrial UV-C Solutions: Safe and Reliable
Thus, while this fungus intrigues space science, on Earth it is a formidable adversary for industrial quality. ERIES® UVC solutions provide a safe, effective, and sustainable answer to eliminate this invisible yet costly risk—while meeting the strict demands of safety, performance, and environmental responsibility.
At ERIES®, we turn this germicidal power into a tool of sanitary security for the food, cosmetics, and pharmaceutical industries, ensuring contamination control, regulatory compliance, and consumer protection.
From Research to Industrial Solutions:
Cladosporium sphaerospermum, resistant to gamma radiation, is neutralized by UV-C.
A clear demonstration that this germicidal technology is a reliable ally for the food, cosmetics, and pharmaceutical industries.
Bibliography
Scientific Sources
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Chang, J.C.H., Ossoff, S.F., Lobe, D.C., et al. (1985). UV inactivation of pathogenic and indicator microorganisms. Applied and Environmental Microbiology, 49(6), 1361–1365.
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Sommer, R., Pribil, W., Appelt, S., et al. (2001). Inactivation of bacteriophages in water by means of non-ionizing radiation (UV-C). Water Research, 35(6), 1387–1393.
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Kowalski, W. (2009). Ultraviolet Germicidal Irradiation Handbook: UVGI for Air and Surface Disinfection. Springer.
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Dadachova, E., & Casadevall, A. (2008). How fungi cope, adapt, and exploit with the help of melanin. Current Opinion in Microbiology, 11(6), 525–531.
Media and Popular Science Sources
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Forbes (2020). Chernobyl fungus eats radiation; space station experiment could help protect astronauts.
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Slate.fr (2020). Le champignon qui se nourrit de radioactivité pourrait protéger les astronautes.
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Futura Sciences (2020). Un champignon de Tchernobyl pourrait protéger les astronautes contre la radiation.
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Science & Vie (2020). Un champignon radio-résistant testé dans l’espace.
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Daily Galaxy (2020). Chernobyl fungus on International Space Station could protect astronauts from radiation.
