Oxidation of Arsenite by Bacteria Isolated from Mine Drainage

摘要

This paper describes a new bacterial strain IWUAS which is able to efficiently oxidize arscnitc (As(Ⅲ)) to arscnate (As(Ⅴ)). The bacteria were isolated from a mine drainage (pH 7.5, As 1.9mg/L) using an As(Ⅲ) (about 200mg/L)-containing ferrous ion-free 9K medium agar plate and cultured in diluted ferrous-ion free 9K. medium. The strain IWUAS is gram-negative and rod-shaped (0.8-1.4 μm). The oxidation rate of As(Ⅲ) depended on the cell concentration. As(Ⅲ) was oxidized in the pH range from pH4.2 to pH 7.5, but the bacteria did not oxidize As(Ⅲ) at pH 3.0. The bacteria gained the energy for the growth from arsenite oxidation and the growth was enhanced with yeast extract.