THE CZC OPERON OF ALCALIGENES-EUTROPHUS CH34 - FROM RESISTANCE MECHANISM TO THE REMOVAL OF HEAVY-METALS

The plasmid-borne etc operon ensures for resistance to Cd2+, Zn2+ and Co2+ ions through a tricomponent export pathway and is associated to v arious conjugative plasmids of A. eutrophus strains isolated from meta l-contaminated industrial areas. The etc region of pMOL30 was reassess ed especially for the segments located upstream and downstream the str uctural genes czc CBA. In cultures grown with high concentrations of h eavy metals, czc-mediated efflux of cations is followed by a process o f metal bioprecipitation. These observations led to the development of bioreactors designed for the removal of heavy metals from polluted ef fluents.