2.9. Antiadhesive role & metal remediation potential of EPS isolated
from LAB isolates
LAB cultures were grown in MRS broth at 37 C and samples
collected every 24 h for a period of 72 h. Twice the volume of 95%
cold ethanol was added to each volume of cell free supernatant, for
exopolysaccharide (EPS) precipitation. Precipitate recovered after
overnight incubation was washed with ethanol, dried and
measured (de Almeida Junior et al., 2015).
Antiadhesive activity of EPS was tested for Escherichia coli, Bacillus
cereus and Staphylococcus aureus (Das, Mukherjee, & Sen,
2009a). The test was repeated thrice and results expressed as
mean ± standard deviation of three independent experiments.
Different concentrations (100e2000 mg/ml) of EPS were separately
incubated with 1 ppm of Cd(II) and Pb(II) solutions for 3 h.
Resulting suspensions were centrifuged and supernatants subjected
to quantification of unbound metals by using appropriate
blanks and standards for calibration. Atomic absorption spectrophotometer
equipped with a flow spoiler (air-acetylene flame,
wave length ¼ 217 nm, slit width of 0.73 nm) and a lamp ignited
with acetylene was employed for this purpose. Software used to
analyze the data was AAWinlab Analyst (Das, Mukherjee, & Sen,
2009b). Results were expressed as mean ± standard deviation of
three independent readings.