title: Long term performance of an arsenite-oxidizing-chlorate-reducing microbial consortium in an upflow anaerobic sludge bed (UASB) bioreactor.
abstract: A chlorate (ClO(3)(-)) reducing microbial consortium oxidized arsenite (As(III)) to arsenate (As(V)) in an upflow anaerobic sludge-bed bioreactor over 550 days operation. As(III) was converted with high conversion efficiencies (>98%) at volumetric loadings ranging from 0.45 to 1.92 mmol As/(L(reactor)d). The oxidation of As(III) was linked to the complete reduction of ClO(3)(-) to Cl(-) and H(2)O, as demonstrated by a molar ratio of approximately 3.0 mol As(III) oxidized per mole of Cl(-) formed and by the greatly lowered ClO(3)(-)-reducing capacity without As(III) feeding. An autotrophic enrichment culture was established from the bioreactor biofilm. A 16S rRNA gene clone library indicated that the culture was dominated by Dechloromonas, and Stenotrophomonas as well as genera within the family Comamonadaceae. The results indicate that the oxidation of As(III) to less mobile As(V) utilizing ClO(3)(-) as a terminal electron acceptor provides a sustainable bioremediation strategy for arsenic contamination in anaerobic environments.
authors.affiliation: Department of Chemical and Environmental Engineering, University of Arizona, PO Box 210011, Tucson, AZ, USA. alexsun@email.arizona.edu
authors.forename: Wenjie
authors.initials: W
authors.lastname: Sun
authors.forename: Reyes
authors.initials: R
authors.lastname: Sierra-Alvarez
authors.forename: Jim A
authors.initials: JA
authors.lastname: Field
mesh_terms: D018053:Arsenites / Q000737:chemistry*; D019149:Bioreactors; D002704:Chlorates / Q000737:chemistry*; D010084:Oxidation-Reduction; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000382:microbiology*
chemical_list: D018053:Arsenites; D002704:Chlorates; D012336:RNA, Ribosomal, 16S; D012722:Sewage; C015001:arsenite