title: Aerobic sulfide production and cadmium precipitation by Escherichia coli expressing the Treponema denticola cysteine desulfhydrase gene.
abstract: The cysteine desulfhydrase gene of Treponema denticola was over-expressed in Escherichia coli to produce sulfide under aerobic conditions and to precipitate metal sulfide complexes on the cell wall. When grown in a defined salts medium supplemented with cadmium and cysteine, E. coli producing cysteine desulfhydrase secreted sulfide and removed nearly all of the cadmium from solution after 48 h. A control strain produced significantly less sulfide and removed significantly less cadmium. Measurement of acid-labile sulfide and energy dispersive X-ray spectroscopy indicated that cadmium was precipitated as cadmium sulfide. Without supplemental cysteine, both the E. coli producing cysteine desulfhydrase and the control E. coli demonstrated minimal cadmium removal.
authors.affiliation: Department of Chemical Engineering, University of California, Berkeley 94720-1462, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Wang
authors.forename: A M
authors.initials: AM
authors.lastname: Lum
authors.forename: S C
authors.initials: SC
authors.lastname: Ozuna
authors.forename: D S
authors.initials: DS
authors.lastname: Clark
authors.forename: J D
authors.initials: JD
authors.lastname: Keasling
mesh_terms: D000332:Aerobiosis; D001709:Biotechnology / Q000379:methods; D002104:Cadmium / Q000378:metabolism*; D011232:Chemical Precipitation; D003542:Cystathionine gamma-Lyase / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D005818:Genetic Engineering; D010957:Plasmids / Q000235:genetics; D013440:Sulfides / Q000378:metabolism*; D014208:Treponema / Q000201:enzymology / Q000235:genetics*
chemical_list: D013440:Sulfides; D002104:Cadmium; D003542:Cystathionine gamma-Lyase