Effects of Environmental Factors on Cyanobacterial Production of Odorous Compounds: Geosmin and 2-Methylisoborneol

Abstract

Geosmin and 2-methylisoborneol (2-MIB), responsible for earthy or musty smell, are a major concern for safe drinking water supplies. This study investigated the effects of environmental factors on odorous compound production and cell growth in cyanobacterial strains. sp. FACHB-1384, a 2-MIB producer, was sensitive to low temperature (<20°C). However, geosmin producers, sp. Chusori and sp. NIER, were sensitive to high light intensity (>100 μmol/m/sec), but not to low temperature. Geosmin concentrations increased under higher nitrate concentrations, being linearly proportional to cell density. A P-limited chemostat showed that P-stress decreased the geosmin productivity and extracellular geosmin amount per cell in sp. NIER. However, only 2-MIB productivity was reduced in sp. FACHB-1374 under P-limitation. The extracellular 2-MIB amount per cell remained constant at all dilution rates. In conclusion, high light intensity and P-stress can contribute to the lower incidence of geosmin, whereas 2-MIB reduction could be attainable at a lower temperature.

Predicting Taste and Odor Compounds in a Shallow Reservoir Using a Three–Dimensional Hydrodynamic Ecological Model

“…In Australia, Jones and Korth [52] showed that the production of geosmin by Anabaena sp. was 0.01 pg/cell, which was a very low concentration compared to the figure found by Li et al Oh et al [53] reported that Anabaena sp. produced extracellular geosmin at 1-2 pg/cell under different nitrogen concentrations.…”

“…was 100-380 ng/µg Chl-a under variable temperature levels. Therefore, the parameter applied in this study was most similar to the values given in Jüttner and Watson [12] and Oh et al [53]. When taste and odor compounds as algal metabolites were modeled, the model accurately simulated the overall concentrations of 2-MIB ( Figure 6) and geosmin ( Figure 7).…”

“…bloomed. Although the model predicted taste and odor compounds realistically for the Jinyang Reservoir in 2016, its robustness may be limited due to the variability in the unitary taste and odor compound productions based on specific species and environmental conditions [12,13,41,42,[51][52][53][54]; the model also clusters cyanobacteria into two groups for taste and odor compound prediction, however, each species within each group could have different taste and odor compound productions and each species could bloom under very specific conditions [35][36][37][38][39][40][41][42][43][44], which the model cannot account for. Hence, future work will need to look at collecting more data and enhancing model functionalities in order to partially overcome such limitations and improve the model accuracy when applied to a new dataset with different input conditions.…”

“…is not the main cause of geosmin, the model seems to have overestimated geosmin. Although the model predicted the geosmin and 2-MIB concentrations relatively well, its robustness may be limited due to the variability in the geosmin and 2-MIB productions based on specific species [12,13,[51][52][53] and environmental factors such as light, temperature, and nutrients [17,36,41,42,54]. Depending on the variation of cyanobacteria species and hydrological and meteorological conditions, the concentration of taste and odor compounds can vary greatly.…”

Effects of Modification of Light Parameters on the Production of Cryptophycin, Cyanotoxin with Potent Anticancer Activity, in Nostoc sp.

“…Light intensity, photoperiod, and light quality have a big influence on the growth and metabolism of photosynthetic organisms including cyanobacteria. This is the reason why many studies exist about the influence of these parameters on cyanobacteria production of secondary metabolites and growth [25][26][27]. For instance, studies focusing on cyanobacterial growth show that Nostoc calcicola has 50% better growth under low light intensities than high intensities [25].…”