Aketagawa J.

Chauncey T. R.

Esau K.

Fortin D.

Hard B. C.

Hatchikian E. C.

Hockett J. R.

King T. E.

Le Faou A.

Magyarosy A. C.

Sugio T.

Webb J. S.

ABSTRACT
 
 The thiosulfate reductase gene (
 phsABC
 ) from
 Salmonella enterica
 serovar Typhimurium was expressed in
 Escherichia coli
 to overproduce hydrogen sulfide from thiosulfate for heavy metal removal (or precipitation). A 5.1-kb DNA fragment containing
 phsABC
 was inserted into the pMB1-based, high-copy, isopropyl-β-
 d
 -thiogalactopyranoside-inducible expression vector pTrc99A and the RK2-based, medium-copy,
 m
 -toluate-inducible expression vector pJB866, resulting in plasmids pSB74 and pSB77. A 3.7-kb DNA fragment, excluding putative promoter and regulatory regions, was inserted into the same vectors, making plasmids pSB103 and pSB107.
 E. coli
 DH5α strains harboring the
 phsABC
 constructs showed higher thiosulfate reductase activity and produced significantly more sulfide than the control strains under both aerobic and anaerobic conditions. Among the four
 phsABC
 constructs,
 E. coli
 DH5α (pSB74) produced thiosulfate reductase at the highest level and removed the most cadmium from solution under anaerobic conditions: 98% of all concentrations up to 150 μM and 91% of 200 μM. In contrast, a negative control did not produce any measurable sulfide and removed very little cadmium from solution. Energy-dispersive X-ray spectroscopy revealed that the metal removed from solution precipitated as a complex of cadmium and sulfur, most likely cadmium sulfide.
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Sang-Weon Bang

Douglas S. Clark

Jay D. Keasling

Crossref

Applied and Environmental Microbiology

Engineering Hydrogen Sulfide Production and Cadmium Removal by Expression of the Thiosulfate Reductase Gene (
 phsABC
 ) from
 Salmonella enterica
 Serovar Typhimurium in
 Escherichia coli

Engineering Hydrogen Sulfide Production and Cadmium Removal by Expression of the Thiosulfate Reductase Gene ( phsABC

Engineering Hydrogen Sulfide Production and Cadmium Removal by Expression of the Thiosulfate Reductase Gene ( phsABC

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