title: Release of arsenic from soil by a novel dissimilatory arsenate-reducing bacterium, Anaeromyxobacter sp. strain PSR-1.
abstract: A novel arsenate-reducing bacterium, designated strain PSR-1, was isolated from arsenic-contaminated soil. Strain PSR-1 was phylogenetically closely related to Anaeromyxobacter dehalogenans 2CP-1(T) with 16S rRNA gene similarity of 99.7% and coupled the oxidation of acetate with the reduction of arsenate. Arsenate reduction was inhibited almost completely by respiratory inhibitors such as dicumarol and 2-heptyl-4-hydroxyquinoline N-oxide. Strain PSR-1 also utilized soluble Fe(III), ferrihydrite, nitrate, oxygen, and fumarate as electron acceptors. Strain PSR-1 catalyzed the release of arsenic from arsenate-adsorbed ferrihydrite. In addition, inoculation of washed cells of strain PSR-1 into sterilized soil successfully reproduced arsenic release. Arsenic K-edge X-ray absorption near-edge structure (XANES) analysis revealed that the proportion of arsenite in the soil solid phase actually increased from 20% to 50% during incubation with washed cells of strain PSR-1. These results suggest that strain PSR-1 is capable of reducing not only dissolved arsenate but also arsenate adsorbed on the soil mineral phase. Arsenate reduction by strain PSR-1 expands the metabolic versatility of Anaeromyxobacter dehalogenans. Considering its distribution throughout diverse soils and anoxic sediments, Anaeromyxobacter dehalogenans may play a role in arsenic release from these environments.
authors.affiliation: Graduate School of Horticulture, Chiba University, Chiba, Japan.
authors.forename: Keitaro
authors.initials: K
authors.lastname: Kudo
authors.forename: Noriko
authors.initials: N
authors.lastname: Yamaguchi
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Makino
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Ohtsuka
authors.forename: Kenta
authors.initials: K
authors.lastname: Kimura
authors.forename: Dian Tao
authors.initials: DT
authors.lastname: Dong
authors.forename: Seigo
authors.initials: S
authors.lastname: Amachi
mesh_terms: D001149:Arsenates / Q000378:metabolism*; D001151:Arsenic / Q000378:metabolism; D058645:Denaturing Gradient Gel Electrophoresis; D008969:Molecular Sequence Data; D009231:Myxococcales / Q000235:genetics / Q000502:physiology*; D010084:Oxidation-Reduction; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D001149:Arsenates; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D001151:Arsenic; C025657:arsenic acid