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.

Arsenic speciation transformation and arsenite influx and efflux across the cell membrane of fungi investigated using HPLC–HG–AFS and in-situ XANES

“…PCC7120, and Anaeromyxobacter sp. strain PSR-1 can change the chemical species of As via oxidation/reduction and methylation/demethylation, and thereby influence the toxicity, mobilization, and availability of As in environment (Yin et al, 2011a;Kudo et al, 2013;Zhao et al, 2013). Other species such as Aspergillus clavatus and Aspergillus niger can sequestrate As into their cytoplasm or adsorb As onto their cell walls and thus transfer As from their surroundings to their own biomass (Č erň anský et al, 2007).…”

Iron Cycling Potentials of Arsenic Contaminated Groundwater in Bangladesh as Revealed by Enrichment Cultivation

“…Some iron reducers can sometimes also reduce arsenate and possess the respiratory arsenate reductase gene arrA (Ohtsuka et al 2013;Kudo et al 2014;Osborne et al 2015). arrA genes closely related to those of Geobacter species have been detected frequently in arsenic rich sediments (Lear et al 2007;H ery et al 2015).…”

Dissimilatory Arsenate Reduction and In Situ Microbial Activities and Diversity in Arsenic-rich Groundwater of Chianan Plain, Southwestern Taiwan

“…lactate, acetate, formate, and aromatic compounds) or inorganic (e.g., hydrogen and sulfide) electron donors [5,6]. In contrast to the detoxification pathway, dissimilatory As(V) reduction (DAsR) plays a major role in the release of As in anoxic environments [7,8]. Notably, dissimilatory As(V)-respiring bacteria (DARB) can reduce both sorbed and dissolved As(V) to As(III) because the enzymes responsible for As(V) reduction are membrane-bound and linked to electron transport chains involved in energy generation [9].…”