Four metals, for example, lead (Pb2þ), nickel
(Ni2
), copper (Cu2þ), and chromium (Cr3þ) ions were
used as lead chloride, nickel chloride, copper sulfate,
and potassium dichromate hexahydrate, respectively.
Isolated bacterial strains were grown on heavy
metal-diluted agar plates. Initial concentration of the
metal was 100 ppm. It was increased gradually by
100 ppm every time on NA plates. MIC was determined when isolates failed to grow even after 5 days
of incubation at 37C.