290
D. Maity et al.
3 Results and Discussion
3.1 Isolation and Screening of Most Potent Bacterial Strain
After serial dilution of the enriched soil sample and transfer of the diluted soil sample
into nutrient agar medium, 29 isolated colonies were obtained. Colony characteristics
of the isolated colonies are shown in Table 1.
After screening, it was found that the strain marked as P25 showed maximum
phenol removal capability (~99.44%) (Table 1), so it was selected for further study.
3.2 Morphological, Biochemical, and Phylogenetic
Characterization of the Isolated Bacterial Strain
Morphological characterization of the isolated bacterial strain P25 is shown in
Tables 2 and 3. Gram characteristics and spore characteristics are shown in Figs. 1,
2, and 3. Physicochemical characteristics are shown in Table 4. The phylogenetic
tree is shown in Fig. 4.
Table 1 Screening of the most potent bacterial strain
Sample
strain
number
Colony size
Colony
pigmentation
Colony
form
Colony
margin
Colony
elevation
% of
phenol
removal
P1
Moderate
White
Circular
Serrate
Flat
83.16
P2
Moderate
White
Irregular
Serrate
Flat
82.86
P3
Small
White
Irregular
Serrate
Flat
80.75
P4
Large
White
Circular
Entire
Flat
80.15
P5
Moderate
White
Circular
Entire
Flat
84.36
P6
Small
Light yellow
Circular
Entire
Raised
81.35
P7
Small
White
Circular
Serrate
Umbonate
80.15
P8
Pinpoint
White
Circular
Serrate
Flat
80.45
P9
Small
Light yellow
Circular
Serrate
Flat
79.25
P10
Moderate
White
Circular
Serrate
Raised
77.44
P11
Moderate
White
Circular
Entire
Flat
82.86
(continued)