鞭毛虫類Ｍｏｎａｓ ｇｕｔｔｕｌａによるカビ臭産生藻類Ｐｈｏｒｍｉｄｉｕｍ ｔｅｎｕｅの分解に及ぼす温度の影響

Abstract

Biodegradation characteristics of cyanobacteria, Phormidium tenue and its metabolites, 2-methylisoborneol(MIB) by protozoan microflagellate, Monas guttula, and the effect of temperature on them were examined in batch culture experiment. The flagellate was found to predate on P.tenue favorably as a food source within a wide temperature range from 10°C to 30°C. Specific growth rate(μ) and generation time(td) of the flagellate were 4.6day-1 and 3.5h-1, respectively at 20°C and 30°C, whereas in the case of 10°C the lag values of μ and td were obtained by 1.9 fold in comparison with the removal ratio of 61% at the first cultivation day and that of 99% at the 2nd day at 30°C, while at 20°C the removal was only about 30% in the first day, but P.tenue could be perfectly reduced at the 2nd day. Although the reduction rate of the P.tenue was slow at the lower temperature of 10°C, the removal reached 98% in the 7th day. Removal rate of P.tenue by the flagellate increased with the increase in temperature and reached maximal value with 4.0h-1 at 30°C. The flagellate could contribute to the degradation of MIB, although the degradation was lower than that of P.tenue. It was found that the microflagellate could favorably predate on P.tenue and degrade its metabolite, MIB emitting musty odor in a wide range of temperature.