Sulfate-reducing bacteria mediate thionation of diphenylarsinic acid under anaerobic conditions

Abstract

Diphenylarsinic acid (DPAA) is often found as a toxic intermediate metabolite of diphenylchloroarsine or diphenylcyanoarsine that were produced as chemical warfare agents and were buried in soil after the World Wars. In our previous study Guan et al. (J Hazard Mater 241-242:355-362, 2012), after application of sulfate and carbon sources, anaerobic transformation of DPAA in soil was enhanced with the production of diphenylthioarsinic acid (DPTAA) as a main metabolite. This study aimed to isolate and characterize anaerobic soil microorganisms responsible for the metabolism of DPAA. First, we obtained four microbial consortia capable of transforming DPAA to DPTAA at a high transformation rate of more than 80% after 4 weeks of incubation. Sequencing for the bacterial 16S rRNA gene clone libraries constructed from the consortia revealed that all the positive consortia contained Desulfotomaculum acetoxidans species. In contrast, the absence of dissimilatory sulfite reductase gene (dsrAB) which is unique to sulfate-reducing bacteria was confirmed in the negative consortia showing no DPAA reduction. Finally, strain DEA14 showing transformation of DPAA to DPTAA was isolated from one of the positive consortia. The isolate was assigned to D. acetoxidans based on the partial 16S rDNA sequence analysis. Thionation of DPAA was also carried out in a pure culture of a known sulfate-reducing bacterial strain, Desulfovibrio aerotolerans JCM 12613(T). These facts indicate that sulfate-reducing bacteria are microorganisms responsible for the transformation of DPAA to DPTAA under anaerobic conditions.

The Invasive Anemone Condylactis sp. of the Coral Reef as a Source of Sulfur- and Nitrogen-Containing Metabolites and Cytotoxic 5,8-Epidioxy Steroids

“…To the best of our knowledge, compound 2 is a natural product isolated for the first time from a living organism. This compound might be derived from thionation of the co-existing nicotinamide ( 3 ) [ 43 ] through a reaction with H 2 S from the conversion of a sulfur source of the ocean by sulfate-reducing bacteria [ 44 ] or similar symbiotic bacteria associated with sea anemones [ 45 , 46 ] ( Scheme 1 ).…”

Contrasting effects of iron reduction on thionation of diphenylarsinic acid in a biostimulated Acrisol

“…3), and we suggest this resulted from the desorption of solid phase-associated inorganic As, rather than a complete mineralization of DPAA due to the following reasons. Firstly, there is no direct evidence that DPAA or PAA can be completely mineralized in flooded or sulfate-reducing soils according to the reported literature (Arao et al 2009;Maejima et al 2011b;Hisatomi et al 2013;Guan et al 2015). Secondly, the reductive dissolution of Fe(III) (hydr)oxides in sulfide soil, as indicated by the increased concentrations of dissolved Fe(II) and HCl-extractable Fe(II) (Fig.…”

“…DPAA thionation in soils requires both sulfate and sufficient carbon sources, and the participation of sulfate-reducing bacteria (SRB) is expected (Guan et al 2012). Studies have also investigated the process of SRB mediated thionation of DPAA (Guan et al 2015) and phenylarsonic acid (PAA) (Hempel et al 2009) in solution and have found that thioarsenate was formed chemically by a reaction of DPAA or PAA with sulfide. Combined results suggest that Fe(III) reduction may have a comparatively strong influence on the mobilization and thionation of DPAA in biostimulated soils.…”