Halomonas BVR 1 isolated from an electronic industry effluent had high level of resistance
to heavy metals like cadmium, lead, zinc and to various antibiotics. Minimum Inhibitory
Concentration (MIC) of the strain toward cadmium and lead was found to be 200 mg L
1 and
400 mg L
1 respectively, while it could tolerate zinc up to 250 mg L
1 and chromium up to
150 mg L
1. The present study proved the genetic contribution of heavy metal resistance in this
strain to be plasmid mediated. Isolation of the plasmid from Halomonas BVR 1 and its subsequent
linearization with Bam H1 confirmed the presence of a plasmid of size >10 kb. Plasmid curing
experiments affirmed plasmid mediated heavy metal resistance. Additionally, genetic transformation
of a non metal resistant lab strain Escherichia coli and the cured strain of Halomonas BVR
1 with the isolated plasmid increased their metal tolerance level by 50% confirming the genetic
determinant to be present in the plasmid.