Abstract
Three species of blue-green algae producing musty odor were isolated and brought into unialgal and actinomycetes-free condition from Saka River System, which has been considered as the main source ofmusty odor problem in Kanamachi Purification Plant.They were subsequently examined for odoriferous substances by means of sensory method and GC-MS.
Two of them, Oscillatoria cortiana andPhormidium favosum, were the newly found 2-methylisoborneol (2MIB) producers, and the first report of attached blue green algae producing 2MIB in Japan. The rest, Oscillatoria agardhii, the well-known geosmin producer in foreign countries, was also the first record on its geosmin production in Japan. This was the different species from the formerly isolated geosmin producer, O. amoena, from Saka River.
After two years preservation period from isolation, it was confirmed that O. cortiana has maintained the 2MIB producing activity. Although there was only onedemonstrative case, it was suggested that O. cortiana had extraordinary potential to produce 2MIB. However, some artificial media developed for blue green algae, such as CT or BG-11, could not give the satisfactory growth of this species. On the other hand, P. favosum, in spite of its good growth in suchmedia, has almost lost the 2MIB producing activity after one year preservation.
Further quantitative studies on kinetics of mustyodor production and physiological and ecological researches on isolates obtained, together with the development of more favorable culture technics, areneeded.
