Odorous compounds from a cyanobacterium in a water purification plant in Central Taiwan

Microorganisms that rapidly proliferated as brown granules and attached to the walls of a storage vessel in a municipal plant for water purification were cultured in the laboratory. From the cultured broth a distinctly offensive odor was detected and filamentous organisms were found predominant. The objectives of this work were to isolate and identify the odor-producing microorganisms and analyze the odorous compounds. An actinomycete, which was not responsible for the production of odor, was found to coexist with the target bacterium, the cyanobacterium. However, a pure culture of cyanobacterium could not be obtained despite a series of purifications. According to morphological characteristics, the cyanobacterium was identified as Nostoc sp. With closed-loop stripping analysis (CLSA), trace organics of odorous compound produced by the isolate were detected at nanogram-per-liter levels. In a batch system, geosmin and MIB showed the highest concentration when cells were in the declining phase. Nostoc sp. was never reported to produce geosmin and MIB. Copyright (C) 1996 Elsevier Science Ltd