Identification of 2-MIB and geosmin producers in Feng-Shen reservoir in south Taiwan

Musty and earthy odor are present in the source water of Feng-Shen waterworks (FSW) in south Taiwan all year round. Although 2-methylisoborneol (2-MIB) and geosmin are responsible for the musty and earthy odor, respectively, the possible odor producers remained unknown. In this study, actinomycetes that produce 2-MIB and geosmin were studied. Based on the 16S rDNA sequence, three species were identified after comparison with the GenBank database at the NCBI. The three species are Streptomyces malaysiensis as a 2-MIB and geosmin producer, Streptomyces caelestis as a 2-MIB producer, and Streptomyces roseoflavus as a geosmin producer. For S. malaysiensis and S. caelestis, the production of MIB and/or geosmin was increased with incubation temperature (20–30 °C) in starch–glutamate broth medium. The optimal MIB, geosmin and biomass occurred at 30 °C. The maximal geosmin/biomass (G/B) and/or MIB/biomass (M/B) also occurred at 30 °C, and sporulating cultures contained more geosmin and/or MIB than nonsporulatig cultures.