108
M. Felix et al.
Table 1 Maximum tolerable
concentration (MTC)
S. No.
Bacteria
Metal
MIC (ppm)
1
Escherichia spp
Lead
260
2
Klebsiella spp.
Lead
250
3
Escherichia spp
Lead
260
4
Pseudomonas spp.
Lead
250
5
Enterobacter spp.
Lead
250
3.3 Determination of Maximum Tolerable Concentration
The maximum tolerable limit of municipal solid waste isolated bacterial strains
against lead was determined by gradually increasing the lead by 10 ppm each time
on a nutrient agar plate. The initial concentration for Lead was 100 ppm. After sterilization, nutrient agar was mixed with heavy metal solution with different concentrations at the ratio of 9:1 and after solidification of media, plates were streaked
with the isolated culture and incubated at 37 °C for a maximum of 48 h. The culture
growth was observed. The culture growing on the initial concentration was again subcultured on higher concentrations by streaking on a new plate (Rojas et al. 2011). The
maximum tolerable concentration was determined when the strains failed to grow
on plates after 48 h (Yamina et al. 2012). Table 1 shows the maximum inhibitory
concentration of Lead.
3.4 Bacteria Consortium for Lead Removal
Several microbial cultures were combined to make a consortium based on the bacteria
that had higher resistance to lead. Using bacterial consortium culture would be much
more effective than a single bacterial culture. Therefore one combination of highly
resistant bacteria consortia was prepared and used in column bioreactor. Table 2
shows the selected bacteria for consortium prepared.
Lead concentration from samples extracted from the column was analyzed. An
interval of one day was taken for different sampling batches for 10 days. The results
show a reduction of lead for the control which was not inoculated with bacteria and
kept constant. Lead reduction ranged from 0.923 to 0.1943 mg/l (Fig. 3). Results show
Table 2 Bacteria selected for
preparation of consortium
S.no
Sample code
bacteria
1
S1-3
Escherichia spp
2
S1-4
Klebsiella spp.
3
S1-9
Pseudomonas spp.
4
S1-10
Enterobacter spp.
M. Felix et al.
Table 1 Maximum tolerable
concentration (MTC)
S. No.
Bacteria
Metal
MIC (ppm)
1
Escherichia spp
Lead
260
2
Klebsiella spp.
Lead
250
3
Escherichia spp
Lead
260
4
Pseudomonas spp.
Lead
250
5
Enterobacter spp.
Lead
250
3.3 Determination of Maximum Tolerable Concentration
The maximum tolerable limit of municipal solid waste isolated bacterial strains
against lead was determined by gradually increasing the lead by 10 ppm each time
on a nutrient agar plate. The initial concentration for Lead was 100 ppm. After sterilization, nutrient agar was mixed with heavy metal solution with different concentrations at the ratio of 9:1 and after solidification of media, plates were streaked
with the isolated culture and incubated at 37 °C for a maximum of 48 h. The culture
growth was observed. The culture growing on the initial concentration was again subcultured on higher concentrations by streaking on a new plate (Rojas et al. 2011). The
maximum tolerable concentration was determined when the strains failed to grow
on plates after 48 h (Yamina et al. 2012). Table 1 shows the maximum inhibitory
concentration of Lead.
3.4 Bacteria Consortium for Lead Removal
Several microbial cultures were combined to make a consortium based on the bacteria
that had higher resistance to lead. Using bacterial consortium culture would be much
more effective than a single bacterial culture. Therefore one combination of highly
resistant bacteria consortia was prepared and used in column bioreactor. Table 2
shows the selected bacteria for consortium prepared.
Lead concentration from samples extracted from the column was analyzed. An
interval of one day was taken for different sampling batches for 10 days. The results
show a reduction of lead for the control which was not inoculated with bacteria and
kept constant. Lead reduction ranged from 0.923 to 0.1943 mg/l (Fig. 3). Results show
Table 2 Bacteria selected for
preparation of consortium
S.no
Sample code
bacteria
1
S1-3
Escherichia spp
2
S1-4
Klebsiella spp.
3
S1-9
Pseudomonas spp.
4
S1-10
Enterobacter spp.