Journal of The School of Marine Science and Technology,Vol.8 No.1
Identification and change in concentration of musty-odor compounds during growth in blue-green algae
Satoko IWASE and Toshihiko ABE
Abstract
The identification of musty-odor compounds and their concentration change during growth in blue-green algae
were investigated in three species of Oscillatoria and six species of Phormidium.Among them,two species,P.M-71
and NIES-512,proved to be musty.In P.M-71,musty-odor substance was identified as geosmin and in P.NIES-512,
2-MIB,on purge/trap GC-MS analysis. In P.M-71,the concentrations of geosmin at 24 and 288 hours after initiation
of growth were 70 and 240ng･(L culture)-1, and 190 and 31 ng･(L culture)-1･A720-1, respectively. In contrast to the
result in P. M-71, 2-MIB in P. NIES-512, the concentrations of 2-MIB at 50 and 312 hours were 790ng and 49μg･
(L culture)-1, and 3.0 and 18pg･(105cells)-1, respectively. These results indicated that the concentration of 2-MIB
in P.NIES-512 was 200 times higher than that of geosmin in P.M-71 at late exponential phase of growth and that
the activity of 2-MIB synthesis increased as cells grew whereas that of geosmin synthesis decreased during growth.
Effect of growth temperature on 2-MIB synthesis was studied in P.NIES-512.The cells grew between 10-35℃
and the concentration of 2-MIB was highest at 25℃. It should be noted that 2-MIB was significantly synthesized even
at 10℃.When the cells were incubated under phosphate-and light-limiting condition (s),the concentration of 2-MIB
was considerably high at exponential growth phase, and then reduced.
These results suggest that musty odor responsible for 2-MIB should occur even in wintertime and in oligotrophic
reservoirs.