Potential of versatile bacteria isolated from activated sludge for the bioremediation of arsenic and antimony

Abstract

Two bacterial strains belonging to the genus Shinella were isolated from the activated sludge of a domestic wastewater treatment plant and could autotrophically oxidize As(III) to As(V) under aerobic conditions. Kinetic studies indicated that the autotrophic As(III) oxidation rate of both strains matched the Monod model well, and strain VKA3 exhibited higher kinetic parameters compared to strain VKA4 (μmax = 124.16 μM/h and Ks = 4407.19 μM vs. μmax = 59.00 μM/h and Ks = 1787.03 μM). The versatility of both strains was expressed through their flexible growth under heterotrophic conditions in the presence of yeast extract and anaerobic As(III) coupled with denitrification. Both strains can oxidize Sb(III) to Sb(V) under aerobic conditions. The arsenite oxidase (aioA) gene, which might be involved in As(III) and Sb(III) oxidation, was detected in the isolated strains. This study demonstrated that the versatile bacteria with potential applications for bioremediation of As and Sb could be obtained from an easily accessible microbiological source.