Isolation and Characterization of Arsenic Tolerant Bacteria …
237
Fig. 1 Isolation of bacteria
from arsenic-contaminated
soil sample
Table 1 Minimum inhibitory
concentration
Bacterial isolates
MIC values (mM)
AsR1
10
AsR2
25
AsR3
70
AsR4
50
AsR(i)
10
AsR(ii)
150
AsR(iii)
150
bacterial isolates can tolerate a high concentration of arsenite salt. Thus the selected
isolates can be used for efficient bioremediation process. Characterization profile of
all the arsenic tolerant isolate has been presented in Table 2. This is to characterize
the bacterial isolates based on morphological character. Amongst the seven bacterial
isolates four were Gram positive in nature and three were Gram negative in nature.
A brief of the observations of biochemical test has been presented in Table 3, to
demonstrate the biochemical nature of the bacterial isolates. Table 3 represents the
sugar utility of the isolates (TSI test), their capability to neutralize the toxic effects
of oxygen metabolites, the ability to hydrolyse starch and to IMV test to characterize
if any of the isolates were enteric in nature.
Table 2 Characterization of arsenic tolerant isolates
Characteristics
of strains
AsR1
AsR2
AsR3
AsR4
AsR(i)
AsR(ii)
AsR(iii)
Colony colour Off-white Off-white White Yellow White
Pale brown Off-white
Colony shape Circular Irregular Ovoid Circular Punctiform Irregular
Circular
Surface
Smooth
Smooth
Rough Smooth Granular
Smooth
Smooth
Elevation
Convex
Flat
Raised Convex Raised
Convex
Convex
Margins
Entire
Undulate Entire Entire
Entire
Undulate
Entire
Opacity
Opaque
Opaque
Opaque Opaque Transparent Transparent Opaque