New Isolated Extremophiles Arsenic Oxidizing Bacteria for the Removal of Arsenic from High- and Low-COD Media

There is an urgent need for the removal of arsenic (As) from groundwater and wastewater as it is a very hazardous heavy metal for human and environmental health. In this research, As-resistant and oxidizing bacteria were isolated from the Maharloo Lake (27 km southeast of Shiraz city) and identified to a great extent. Three isolated bacillus-shaped strains (called F5, F6 and F7) tolerated up to 1 M AsNaO2, grew up to 3.5 M NaCl and pH 12, and consumed NaSCN and Na2S2O3. The molecular analysis confirmed the originality of the strains to a high extent. The As absorption rate by these bacteria was measured by the atomic absorption method, and their effect was examined on a water sample from the south of Kerman city (Iran) and a synthetic wastewater sample with a chemical oxygen demand (COD) of about 180,000 kg/m3 that was able to absorb high levels of arsenic.