Aerobic sulfide production and cadmium precipitation by Escherichia coli expressing the Treponema denticola cysteine desulfhydrase gene.
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.
Wang
C L
CL
Department of Chemical Engineering, University of California, Berkeley 94720-1462, USA.
Lum
A M
AM
Ozuna
S C
SC
Clark
D S
DS
Keasling
J D
JD
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*
D013440:Sulfides; D002104:Cadmium; D003542:Cystathionine gamma-Lyase