Studies on the mercury volatilizing enzymes in nitrogen-fixing Beijerinckia mobilis.

Beijerinckia mobilis KDr2, a broad-spectrum, mercury-resistant nitrogen-fixing organism, possesses multiple metal-resistance properties. Mercuric reductase and organomercurial lyase activities of this bacterial strain were determined using different mercury compounds and heavy metal salts of copper, nickel, cobalt, cadmium, silver, zinc, lead and arsenate as inducers and substrates. Mercuric reductase was partially purified and the effect of some enzyme inhibitors and heavy metal ions on the enzyme activity was studied. The enzyme activity was completely inhibited by CdCl2, Bi(NO3)3 and KCN at 10(-5) M and by AgNO3, CoCl2 and CuSO4 at 10(-4) M.