|Wang, C. L.; Lum, A. M.; Ozuna, S. C.; Clark, D. S.; Keasling, J. D.
|Aerobic sulfide production and cadmium precipitation by Escherichia coli expressing the Treponema denticola cysteine desulfhydrase gene
|Appl Microbiol Biotechnol
|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.