2022 年 68 巻 3 号 p. 117-123
To develop an effective technology for conversion of inorganic arsenic to methylated organic arsenic compounds by using microorganisms, we have searched for microorganisms to have the arsenic methylation ability that are adequately applicable for the detoxification process. As a result, we have isolated arsenic-methylating bacteria Cellulomonas sp. K31.
The growth of strain K31 was also observed in 400 mg As/L arsenic medium. The percent of organic methylated arsenic excreted into the medium by strain K31 showed 91.6% of total arsenic compounds when strain K31 was cultured in the medium containing 5.0 mg As/L arsenic for 4 days. Under this condition Productions of trimethylarsenic oxide and arsenobetaine were 36.1% and 2.5%, respectively. The methylation of inorganic arsenic was evaluated using intracellular extract from strain K31. The result was that total yield of methylated organic arsenic compounds was 57.0% (after 2 h of incubation at pH 6.5 and 40°C), of which trimethyl arsenic compounds accounted for 17.9%. The percentages of methylated organic arsenic compound were the highest value compared to the previous arsenic-methylating bacteria.
