Purpose: Evaluation of Cr (VI) removal by indigenous chromium resistant bacterial strains alone and in
combination with Eichornia sp.
Methods: Three chromium resistant bacterial strains S-4
Ochrobactrum grignonense
, SF-5
Bacillus
sp.
and S-6 Ochrobactrum pseudogrignonenses were isolated from industrial effluent. The isolated
chromium-resistant bacterial strains were subjected to heavy-metal resistance profiling. Cr (VI)
reduction was evaluated in mobilized as well as immobilized forms. The phytoremediation potential of
Eichornia sp. in conjunction with chromium resistant bacterial isolates was also determined. Fourier
transform infra-red (FTIR) spectroscopy was performed to rule out the involvement of various functional
groups in the binding activity of Cr (VI).
Results: Three bacterial strains resisted up to 1000 μg/mL of potassium dichromate (K
2CrO
4). Bacterial
strains S-4, SF-5 and S-6 showed significant Cr (VI) removal in mobilized state (84.93, 85.85 and 83.97
% respectively) compared with immobilized state (41.27, 37.99, 37.96 %) at an initial concentration of
500 μg/mL of chromate. Bacterial strains caused reduction in chromate uptake in inoculated plants
relative to control plants. FTIR spectra revealed significant changes in the absorption peaks, reflecting
the binding of Cr (VI) ions with bacterial cell surface under stress conditions.
Conclusion: The selected isolates tested possess the ability to remove Cr (VI) synergistically with
Eichornia sp.
