Pyruvic oxime nitrification and copper and nickel resistance by a cupriavidus pauculus, an active heterotrophic nitrifier-denitrifier

Heterotrophic nitrifiers synthesize nitrogenous gasses when nitrifying ammoniumion. A Cupriavidus pauculus, previously thought an Alcaligenes sp. and noted as an active heterotrophic nitrifier-denitrifier, was examined for its ability to produce nitrogen gas (N₂) and nitrous oxide (N₂O) while heterotrophically nitrifying the organic substrate pyruvic oxime [CH₃-C(NOH)-COOH]. Neither N₂ nor N₂O were produced.Nucleotide and phylogenetic analyses indicated that the organism is amember of a genus (Cupriavidus) known for its resistance tometals and itsmetabolism of xenobiotics.The microbe (a Cupriavidus pauculus designated as C. pauculus strain UM1) was examined for its ability to perform heterotrophic nitrification in the presence of Cu²⁺ and Ni2+ and to metabolize the xenobiotic phenol. The bacterium heterotrophically nitrified well when either 1mM Cu²⁺ or 0.5mM Ni²⁺ was present in either enriched or minimal medium. The organism also used phenol as a sole carbon source in either the presence or absence of 1mM Cu²⁺ or 0.5mM Ni2+.The ability of this isolate to perform a number of different metabolisms, its noteworthy resistance to copper and nickel, and its potential use as a bioremediation agent are discussed.