[Arsenic oxidation by the heterotrophic bacteria Pseudomonas putida and Alcaligenes eutrophus]

Two heterotrophic bacteria, Pseudomonas putida 18 and Alcaligenes eutrophus 280, were isolated from gold-arsenic deposits. The bacteria oxidize As(III) to As(V) at pH 6-9 and temperatures 4-28 and 28 degrees C respectively. The oxidation is accompanied by a decrease in the pH of the medium. The rate of the oxidation directly depends on the number of cells in the inoculum.