2009 Volume 56 Issue 4 Pages 153-158
Biomethylation of arsenic is usually considered as a detoxification of arsenic because toxicity of most organic methylated arsenic is much less than that of inorganic arsenic. We investigated the feasibility of a novel bioremediation using an arsenic methylating bacterium. An arsenic methylating bacterium Bacillus cereus strain R2, isolated from soil in Miyazaki, was evaluated for growth characteristics and arsenic metabolism. The growth of strain R2 was inhibited in 50.0 mg As/l arsenic medium. Strain R2 metabolized arsenite (<5.0 mg As/l) to nonvolatile species such as monomethylarsonic acid, dimethylarsinic acid and trimethylarsenic oxide effectively. The percentage of organic methylated arsenic excreted into the medium by strain R2 showed 89.0% of total arsenic compounds when strain R2 was cultured aerobically in the medium containing 0.1 mg As/l of arsenite and 1.0 g/l of glucose for four days.
