Conclusion
In this study, isolated strains were used to evaluate the syner-gistic effects of bacterial mixtures on bioremediation efficiency. At the end of the experimental period, the bacterial mixtures were found to be the most effective bacterial method, in comparison toindividual culture methods. Compared with single strain cultures,the bacterial mixtures showed higher growth rate, urease activity, and resistance to heavy metals. Also, we demonstrated thatthe bacterial mixtures exhibited a considerably higher heavy metalbioremediation capacity than individual cultures, which might dueto higher bacterial cell density at high levels of heavy metals.According to the column test results, the highest bioremediation efficiencies were noted for Pb, while the lowest removal efficiencies were detected for Cd. Bioremediation with the bacterial mixtures of isolated strains is an effective method for heavy metal removal from contaminated environments. This may prove to be a good strategy for developing an effective, efficient, and economic method ofheavy metal bioremediation, and the introduction of these indigenous bacteria could be used for contaminated soil bioremediationwithout disturbing the target environment.
Acknowledgements This research was supported by Basic Science Research Programthrough the National Research Foundation of Korea (NRF) fundedby the Ministry of Education (NRF-2015R1D1A1A01056788).