Accumulation and Release of Geosmin during the Growth Phases of Anabaena circinalis (Kutz.) Rabenhorst

• Published in: Water science and technology 1992-01, Vol.25 (2), p.185-190
• Main Authors: Rosen, B H, MacLeod, B W, Simpson, M R
• Format: Article
• Language: English
• Subjects: 2-Methylisoborneol; Acetone; Algae; Anabaena; Anabaena circinalis; Cell culture; Chlorophyll; Chlorophyll a; Culture media; Detection; Flame ionization; Gas chromatography; Geosmin; Growth media; Ionization; Lysis; Odor; Odour; Polycarbonate; Raw water; River water; Rivers; Stationary phase; Stripping
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.1992.0051

Anabaena circinalis (Kutz.) Rabenhorst was isolated during a taste and odor episode characterized by high concentrations of geosmin, with raw water containing up to 45 ng geosmin/L. This species has been successfully cultured with sustained geosmin synthesis on both sterile river water and defined medium. Gas chromatography of cellular extracts and closed-loop stripping of growth media indicated that this organism produces geosmin and not 2-methylisoborneol (MIB). With cultures we examined the changes in cell-associated geosmin, chlorophyll and released geosmin during exponential and stationary growth phases of Anabaena. Cell-associated geosmin samples were collected daily from cultures and filtered onto a polycarbonate filter, extracted in acetone, and quantified by capillary gas Chromatograph using flame ionization detection. Media-associated geosmin was quantified from algae-free filtrates from each culture concentrated by closed-loop stripping and analyzed as above. Cell-associated geosmin averaged at 8 × 10−6 ng geosmin/cell in the exponential phase and dropped to 2.5 × 10−6 ng geosmin/cell in the stationary phase of growth. The loss in cell-associated geosmin was accompanied by an increase in geosmin released into the media. Media-associated geosmin reached 12 ng/mL in the stationary phase. Apparently cell lysis in the stationary phase caused the release of cell-associated geosmin into the media. Cell-associated geosmin was closely correlated with filament number (average r2 from 4 experiments =0.96) during the exponential growth phase and was correlated with chlorophyll a (average r2 from 3 experiments =0.95).