Bacterial Populations Associated with the Oxidation and Reduction of Arsenic in an Unsaturated Soil
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- 作者：Richard E. Macur ; Colin R. Jackson ; Lina M. Botero ; Timothy R. Mcdermott ; and William P. Inskeep
- 刊名：Environmental Science & Technology
- 出版年：2004
- 出版时间：January 1, 2004
- 年：2004
- 卷：38
- 期：1
- 页码：104 - 111
- 全文大小：182K
- 年卷期：v.38,no.1(January 1, 2004)
- ISSN：1520-5851
文摘
Microbial populations responsible for the oxidation andreduction of As were examined in unsaturated (aerobic) soilcolumns treated with 75 
M arsenite [As(III)] or 250 Marsenate [As(V)]. Arsenite [As(III)] was rapidly oxidized toAs(V) via microbial activity, whereas no apparentreduction of As(V) was observed in the column experiments.Eight aerobic heterotrophic bacteria with varying Asredox phenotypes were isolated from the same columns.Three isolates, identified as Agrobacterium tumefaciens-,Pseudomonas fluorescens-, and Variovorax paradoxus-likeorganisms (based on 16S sequence), were As(III) oxidizers,and all were detected in community DNA fingerprintsgenerated by PCR coupled with denaturing gradient gelelectrophoresis. The five other isolates were identified (16Sgene sequence) as A. tumefaciens, Flavobacterium sp.,Microbacterium sp., and two Arthrobacter sp.-like organismsand were shown to rapidly reduce As(V) under aerobicconditions. Although the two A. tumefaciens-like isolatesexhibited opposite As redox activity, their 16S rDNA sequences(~1400 bp) were 100% identical, and both were shownto contain putative arsC genes. Our results support thehypothesis that bacteria capable of either oxidizing As(III)or reducing As(V) coexist and are ubiquitous in soilenvironments, suggesting that the relative abundance andmetabolic activity of specific microbial populations playsan important role in the speciation of inorganic As in soil porewaters.
M arsenite [As(III)] or 250 Marsenate [As(V)]. Arsenite [As(III)] was rapidly oxidized toAs(V) via microbial activity, whereas no apparentreduction of As(V) was observed in the column experiments.Eight aerobic heterotrophic bacteria with varying Asredox phenotypes were isolated from the same columns.Three isolates, identified as Agrobacterium tumefaciens-,Pseudomonas fluorescens-, and Variovorax paradoxus-likeorganisms (based on 16S sequence), were As(III) oxidizers,and all were detected in community DNA fingerprintsgenerated by PCR coupled with denaturing gradient gelelectrophoresis. The five other isolates were identified (16Sgene sequence) as A. tumefaciens, Flavobacterium sp.,Microbacterium sp., and two Arthrobacter sp.-like organismsand were shown to rapidly reduce As(V) under aerobicconditions. Although the two A. tumefaciens-like isolatesexhibited opposite As redox activity, their 16S rDNA sequences(~1400 bp) were 100% identical, and both were shownto contain putative arsC genes. Our results support thehypothesis that bacteria capable of either oxidizing As(III)or reducing As(V) coexist and are ubiquitous in soilenvironments, suggesting that the relative abundance andmetabolic activity of specific microbial populations playsan important role in the speciation of inorganic As in soil porewaters.