An arsenic(III)-oxidizing bacterial population: selection, characterization, and performance in reactors

Abstract

Aims: To select an autotrophic arsenic(III)-oxidizing population, named CASO1, and to evaluate the performance of the selected bacteria in reactors. Methods and Results: An As(III)-containing medium without organic substrate was used to select CASO1 from a mining environment. As(III) oxidation was studied under batch and continuous conditions. The main organisms present in CASO1 were identified with molecular biology tools. CASO1 exhibited significant As(III)-oxidizing activity between pH 3 and 8. The optimum temperature was 25°C. As(III) oxidation was still observed in the presence of 1000 mg l )1 As(III). In continuous culture mode, the As(III) oxidation rate reached 160 mg l )1 h )1 . The CASO1 consortium contains at least two organisms -strain b3, which is phylogenetically close to Ralstonia picketii, and strain b6, which is related to the genus Thiomonas. The divergence in 16S rDNA sequences between b6 and the closest related organism was 5AE9%, suggesting that b6 may be a new species. Conclusions: High As(III)-oxidizing activity can be obtained without organic nutrient supply, using a bacterial population from a mining environment. Significance and Impact of the Study: The biological oxidation of arsenite by the CASO1 population is of particular interest for decontamination of arsenic-contaminated waste or groundwater.

Structural and functional genomics of plasmid pSinA of Sinorhizobium sp. M14 encoding genes for the arsenite oxidation and arsenic resistance

“…Osborne et al, 2010). Several pure cultures of bacterial strains (Rhine et al, 2006), as well as microbial consortia (Battaglia-Brunet et al, 2002) able to transform As (III) to As(V) have been isolated. For some of them, biogeochemical function in the environment has been described (Connon et al, 2008;Drewniak et al, 2010) and/or a practical application in bioremediation has been proposed (e.g.…”

Biological Oxidation of Arsenite in Strong Acid Water

“…The oxidation reaction of arsenite to arsenate depends on pH. At pH<2.0, the oxidation reaction is represented as follows 10) . The standard free-energy change for this reaction is -129.65 kJmol −1 .…”

“…Battaglia-Brunet, et al 10) found that the biofilm on the internal surface of the glass reactor developed as CASO1 oxidized arsenite, and considered that the high oxidation rate may have resulted from the presence of this biofilm. In this study, the formation of aggregates was observed as the arsenite oxidation proceeded.…”

“…These bacteria can gain energy for growth from the oxidation of arsenite. Battaglia-Brunet, et al 10) selected an arsenite-oxidizing population, named CASO1, from mine drainage. CASO1 exhibited significant arseniteoxidizing activity between pH 3 and pH 8.…”

Arsenic redox transformation by Pseudomonas sp. HN-2 isolated from arsenic-contaminated soil in Hunan, China

“…Some As(III)-oxidizing bacteria are able to oxidize As(III) at low pH (≤4), e.g., Sulfolobus acidocaldarius (Sehlin and Lindstrom, 1992) and Thiomonas arsenivorans (Dastidar and Wang, 2009). An autotrophic As(III)-oxidizing population (CASO1) was isolated that exhibited As(III) oxidation activity between pH 3-8 (Battaglia-Brunet et al, 2002). However, most of the known As(III)-oxidizing bacteria demonstrated optimum oxidation at near-neutral pH.…”