1991 年 37 巻 2 号 p. 83-88
Biomethylation of selenium (Se) by freshwater green algae, Ankistrodesmus sp., Chlorella vulgaris and Selenastrum sp., which had been isolated from the Tone River and Lake Kasumigaura in Japan, were investigated. All of the three algae produced methylated Se compounds from the corresponding inorganic compounds. The formation of trimethylselenonium ion (TMSe) by algae reached a plateau 2-4 d after culturing and the amount of Se an TMSe was less than about 0.001% of the added Se. TMSe was also found in the algae and was in the range from 0.04 to 0.3% of total-Se accumulated in the algae. Dimethylselenide (DMSe) was found in the headspace gases of the cultured flask and was in the range from 0.001 to 0.016% of the added Se. Total-Se accumulated in the algae was in the range from 0.002 to 0.2% of added Se. The presence of arsenic in the medium inhibited DMSe formation in the algae. Green algae in the freshwater ecosystems might be related to methylation of Se, and biomethylation of Se by green algae is thought to be one of the detoxification processes.
