Properties of Arsenic-methylating and Arsenic-removing Bacterium <i>Bordetella petrii</i> Strain KC42

The properties of Bordetella petrii strain KC42 isolated from the soil in Miyazaki Prefecture were investigated in terms of arsenic methylation and removal in this study. No differences were observed in the growth of strain KC42 between As(III)- and As(V)-supplemented culture medium. Strain KC42 metabolized inorganic arsenic (<5.0 mgAs/L) to nonvolatile species such as monomethylarsonic acid, dimethylarsinic acid, trimethylarsenic oxide and arsenobetaine effectively. In culture supplemented with 0.2 mg As/L As(V), 98.7% of the arsenic remaining in the supernatant was found to be methylated organic arsenic compounds. An analysis of the arsenic adsorbed to the bacterial cell walls revealed that most of the arsenic removed from culture medium was accounted by cell wall adsorption for both As(III)- and As(V)-supplementation, and that in both cases, all of the adsorbed arsenic was in the As(III) form. These results demonstrate that strain KC42 possesses arsenic-methylating and arsenic-removing capabilities, and may therefore be used in the bioremediation of arsenic.