[EMERGING]Emerging
Metabolites of Wallemia sebi measured at water activity below common mold-growth thresholds
Laboratory work on Wallemia sebi, a fungus common in house dust, reported growth and metabolite production at water activity levels below the thresholds commonly cited for indoor mold growth.
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Last reviewed August 30, 2026.
What they studied
- Isolates of Wallemia sebi, a xerophilic fungus frequently recovered from house dust.
- Culture across a range of water activity levels, including values below 0.80.
- Chemical identification of the extrolites produced and testing of their cytotoxicity.
What they found
- The authors reported growth at water activity as low as 0.69.
- Walleminone and wallimidione were among the metabolites identified.
- The identified compounds were reported to be cytotoxic in the assays used.
What this study does not establish
- Laboratory culture conditions, not measured indoor environments.
- No airborne concentrations or occupant exposures were measured.
- Cytotoxicity assays do not establish human health outcomes.
- This entry reports the study. It is not a statement about any building Sage Co. designs or constructs.
Source
Desroches TC, McMullin DR, Miller JD (2014). Extrolites of Wallemia sebi, a very common fungus in the built environment. Indoor Air 24(5):533–542.
Wallemiawater activityhouse dustmetabolites
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