A novel arsenate respiring isolate that can utilize aromatic substrates

A novel anaerobic bacterium was isolated from the sediment of Onondaga Lake (Syracuse, NY), which can use arsenate [As(V)] as a respiratory electron acceptor. The isolate, designated strain Y5 is a spore-forming, motile rod, with lateral flagella. It is Gram-negative though it phylogenetically falls within the low G + C Gram-positive organisms. In addition to the more usual electron donors such as lactate and succinate, strain Y5 also can use H(2)+ CO(2) chemoautotrophically and metabolize aromatic compounds such as syringic acid, ferulic acid, phenol, benzoate and toluene, coupled to arsenate reduction. Aside from As(V), nitrate, sulfate, thiosulfate and Fe(III) can also serve as electron acceptors. Based on 16S rDNA phylogeny and its physiological characteristics, strain Y5 was identified as most closely related to the genus Desulfosporosinus. The ability of microorganisms to reduce arsenate for respiration appears to be widely distributed and may be relevant in the biogeochemical cycling of arsenic in environments containing mixed contaminants.