106
M. Felix et al.
2.5 Screening of Heavy Metal Resistant Bacteria
The isolates were cultured on various heavy metals concentrations and were incubated for 42 h at 37 °C. Different concentrations of Copper, Lead, and Nickel were
prepared and mixed with sterilized nutrient agar, plated, and inoculated with the
isolates. The medium was mixed at the ratio of 9:1. 1 ml of stock heavy metal solution
of different concentrations was added to 9 ml of medium. The concentration of each
element was increased every time bacterial growth was observed until when there was
no growth at maximum concentration. Bacteria which grow at higher concentration
were selected and there maximum tolerable concentration were recorded.
Bacteria observed to grow at higher concentrations of Copper, Lead, and Nickel
among the 42 isolates screened were selected for further study in column test using
bacterial consortium.
2.6 Bacteria Resistance to Heavy Metals
The isolates were cultured on various heavy metals concentrations and were incubated for 48 h at 37 °C. Different concentrations of Lead were prepared and mixed
with sterilized nutrient agar, plated, and inoculated with the isolates. The medium
was mixed at the ratio of 9:1. 1 ml of stock heavy metal solution of different concentrations was added to 9 ml of medium. Among 42 isolates screened, bacteria observed
to grow at higher concentrations of Lead were selected for further study in column
test using bacterial consortium.
2.7 Maximum Tolerable Concentration
The maximum tolerable concentration of isolated bacterial strains against their
respective heavy metals was determined by gradually increasing the heavy metals by
10 ppm each time on the nutrient agar plate. The initial concentration for all heavy
metals 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 sub-cultured on higher concentrations by streaking
on a new plate (Rojas et al. 2011). The maximum Inhibitory concentration was
determined when the strains failed to grow on plates after 48 h (Yamina et al. 2012).
M. Felix et al.
2.5 Screening of Heavy Metal Resistant Bacteria
The isolates were cultured on various heavy metals concentrations and were incubated for 42 h at 37 °C. Different concentrations of Copper, Lead, and Nickel were
prepared and mixed with sterilized nutrient agar, plated, and inoculated with the
isolates. The medium was mixed at the ratio of 9:1. 1 ml of stock heavy metal solution
of different concentrations was added to 9 ml of medium. The concentration of each
element was increased every time bacterial growth was observed until when there was
no growth at maximum concentration. Bacteria which grow at higher concentration
were selected and there maximum tolerable concentration were recorded.
Bacteria observed to grow at higher concentrations of Copper, Lead, and Nickel
among the 42 isolates screened were selected for further study in column test using
bacterial consortium.
2.6 Bacteria Resistance to Heavy Metals
The isolates were cultured on various heavy metals concentrations and were incubated for 48 h at 37 °C. Different concentrations of Lead were prepared and mixed
with sterilized nutrient agar, plated, and inoculated with the isolates. The medium
was mixed at the ratio of 9:1. 1 ml of stock heavy metal solution of different concentrations was added to 9 ml of medium. Among 42 isolates screened, bacteria observed
to grow at higher concentrations of Lead were selected for further study in column
test using bacterial consortium.
2.7 Maximum Tolerable Concentration
The maximum tolerable concentration of isolated bacterial strains against their
respective heavy metals was determined by gradually increasing the heavy metals by
10 ppm each time on the nutrient agar plate. The initial concentration for all heavy
metals 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 sub-cultured on higher concentrations by streaking
on a new plate (Rojas et al. 2011). The maximum Inhibitory concentration was
determined when the strains failed to grow on plates after 48 h (Yamina et al. 2012).