Frequent off-flavor events caused by geosmin and 2-methylisoborneol (MIB) have attracted research on the main producers, cyanobacteria. This study evaluated the effects of light and temperature on the odor production of MIB-producing Pseudanabaena sp. Lauterborn and geosmin-producing Anabaena ucrainica (Schhorb.) Watanabe. The maximum MIB production and lowest growth rate (indicated by the chlorophyll a (Chi a)) were observed at 35 degrees C compared with that at 10 degrees C and 25 degrees C Cultures grown under a light intensity of 60 mu mol photons m(-2) s(-1) demonstrated the highest MIB production and minimum growth rate, whereas the minimum MIB production and maximum growth rate were obtained under 10 mu mol photons m(-2) s(-1). Similar patterns were observed for geosmin production. A. ucrainica had the highest geosmin production and lowest Chl a concentration under 10 degrees C and 60 mu mol photons m(-2) s(-1). Moreover, greater proportions of geosmin and MIB were released into extracellular under growth-inhibiting temperatures and light intensities. An inverse correlation between odor production and the cell growth rate was suggested, and this relationship may reflect the competition for substrates of odor and Chl a synthesis. Thus, the accumulation of geosmin and MIB was probably the result of decreased cellular metabolic activity in cyanobacteria. (C) 2014 Elsevier Ltd. All rights reserved.