Geosmin Production and Excretion in a Planktonic and Benthic Oscillatoria

Abstract

Geosmin and carotenoid contents for the benthic Oscillatoriabrevis and the planktonic Oscillatoriabornetii were examined under different growth conditions. The results obtained when the effects of light intensity, light quality and growth rate were examined indicate that geosmiri could be a by-product of the isoprenoid pathway leading to chlorophyll and carotenoids in Oscillatoria and not a overflow product of this pathway as earlier suggested. The connection between geosmin and pigment synthesis suggests that geosmin production by a cyanobacterial bloom might be lowest at the surface and increase with depth in the water column. Geosmin is also found to be an intracellular compound, which is released upon death and decay of the organisms.

Effects of light and temperature on the odor production of 2-methylisoborneol-producing Pseudanabaena sp. and geosmin-producing Anabaena ucrainica (cyanobacteria)

“…Naes et al (1985) used geosmin-producing Oscillatoria brevis to show a decrease in geosmin production occurs with a decrease in the chlorophyll content under different light intensities. This conclusion agreed with results obtained in planktonic Anabaena circinalis and benthic Oscillatoria (Bowmer et al, 1992;Utkilen and Frøshaug, 1992). However, the results of Wu and Jüttner (1988a) implied a negative correlation between geosmin synthesis and the growth rate of Fischerella muscicola ATCC 29114, in which geosmin production at 20 C was lower than that at the optimum growth temperature (30 C).…”

“…Combined with other studies on N-limited conditions (Wu et al, 1991;Blevins et al, 1995;Saadoun et al, 2001), the observed inverse correlation is common among odor-producing cyanobacteria. The comparison of geosmin production with increasing Chl a content was not a cause of concern, possibly because a reasonable cause for the direct correlation was previously explained in the studies by Naes et al (1985), Utkilen and Frøshaug (1992), and Bowmer et al (1992). To the best of our knowledge, the present paper is the first report on the effects of temperature and light on MIB-producing cyanobacteria.…”

EXPRESSION OF THE GEOSMIN SYNTHASE GENE IN THE CYANOBACTERIUM ANABAENA CIRCINALIS AWQC3181

“…These initial findings were later supported by similar studies using A. circinalis (Bowmer et al. 1992) and benthic and planktonic Oscillatoria (Utkilen and Froshaug 1992), where the production of geosmin correlated with chl a and/or carotenoid measurements. The above reports concluded that the concomitant decrease in geosmin and chl a /carotenoids most likely linked geosmin production to an isoprenoid pathway.…”

Biochemistry and genetics of taste- and odor-producing cyanobacteria

“…Similarly, studies with Anabaena (syn. Dolichospermum) circinalis and benthic and planktonic Oscillatoria also found a correlation between geosmin production and chla and/or carotenoid measurements, and concluded that the concomitant decrease of geosmin and the ratio of chla/carotenoids most likely linked geosmin production to an isoprenoid pathway (Bowmer et al, 1992;Utkilen and Froshaug, 1992).…”