GEOSMIN AS AN ODOROUS METABOLITE IN CULTURES OF A FREE-LIVING AMEBA, VANNELLA SPECIES (GYMNAMOEBIA, VANNELLIDAE)

Geosim was identified as the cause of a distinct earth/grassy odour detected in cultures of a free-living amoeba, Vannella species. Volatile components of cell lysates were isolated and concentrated by the Closed Loop Stripping method. Capillary gas chromatography/mass spectrometry was used to identify odorous compounds. Bacterial symbionts observed in the cytoplasm of the amoebae may be responsible for production of the geosmin. This appears to be the first report of odorous compounds associated with a free-living protozoan and suggests that in some circumstances, Vannella sp. may contribute to taste and odour problems in drinking water.