180

Bioremediation for Sustainable Environmental Cleanup

of open biotechnological applications. The most pressing issue is developing genetically modified

bacteria with an acceptable degree of environmental assurance for field release in bioremediation.

The efforts to evaluate the performance of modified bacteria under severe environmental conditions

include endurance and horizontal gene transfer capacity, that may influence the native microflora

of the environment. To avoid this, field bacteria are specially developed for in vitro bioremediation.

It is unclear if the intentional discharge of genetically engineered bacteria for bioremediation has

any negative impact on native microorganisms (Sayler and Ripp 2000). As a result, the survival of

genetically modified microorganisms in a hostile environment remains a major concern.

10.8 Conclusions

Several studies have been conducted for the bioremediation of toxic metals from the environment.

Microbial mediated bioremediation is found to be a sustainable approach. However, certain

areas need to be more focused on and explored so that they can be applied for commercial use.

As bioremediation in most studies is successful in the laboratory and controlled conditions, hence

there is a need to explore the mechanism to carry out bioremediation under natural environment

without controlled conditions. Besides this, GMOs are being used due to their high capability to

perform bioremediation in comparison to wild-type microbial strains. However, there are several

risks associated with this technology, such as ecological disturbance and horizontal gene transfer,

which cause the limited use of GMOs in bioremediation. Extremophiles need to be explored more,

and there might be unculturable microbes present in the environment, hence the need to develop the

process to culture these unexplored microbes. The process development for scale-up is required for

more commercial applications.

Acknowledgments

This work is supported by Grant no. BT/RLF/Re-entry/ 40/ 2017 from the Department of Biotechnology

(DBT), Ministry of Science and Technology and SERB project file no: EEQ/2020/000614 Govt. of

India. We acknowledge the CSIR pool scientific scheme Grant no. 9103, Govt. of India. Pictures are

created by using www.biorender.com.

References

Abdel-Gadir, A., R. Berber, J. B. Porter, P. D. Quinn, D. Suri, P. Kellman et al. 2016. Detection of metallic cobalt

and chromium liver deposition following failed hip replacement using T2* and R2 magnetic resonance. J.

Cardiovasc. Magn. Reson. 18: 29.

Abd-Elnaby, H., G. M. Abou-Elela and N. A. El-Sersy. 2011. Cadmium resisting bacteria in Alexandria Eastern

Harbor (Egypt) and optimization of cadmium bioaccumulation by Vibrio harveyi. Afr. J. Biotech. 10:

3412–3423.

Abedin, Md. J., J. Cotter-Howells and A. A. Meharg. 2002. Arsenic uptake and accumulation in rice (Oryza sativa L.)

irrigated with contaminated water. Plant Soil. 240: 311–319.

Akcil, A., C. Erust, S. Ozdemiroglu, V. Fonti and F. Beolchini. 2015. A review of approaches and techniques used in

aquatic contaminated sediments: metal removal and stabilization by chemical and biotechnological processes.

J. Clean. Prod. 86: 24–36.

Al Khateeb, W. and H. Al-Qwasemeh. 2014. Cadmium, copper and zinc toxicity effects on growth, proline content

and genetic stability of Solanum nigrum L., a crop wild relative for tomato; comparative study. Physiol. Mol.

Biol. Plants. 20: 31–39.

Al Osman, M., F. Yang and I. Y. Massey. 2019. Exposure routes and health effects of heavy metals on children.

Biomet.: Int. J. Role. Met. Ion. Biol. Biochem. Med. 32: 563–573.

Ancion, P. Y., G. Lear, A. Dopheide and G. D. Lewis. 2013. Metal concentrations in stream biofilm and sediments and

their potential to explain biofilm microbial community structure. Environ. Pollut. 173: 117–124.

Andreoli, V. and F. Sprovieri. 2017. Genetic aspects of susceptibility to mercury toxicity: an overview. Int. J. Environ.

Res. Public Health. 14: 93.

Arya, S. K. and B. K. Roy. 2011. Manganese induced changes in growth, chlorophyll content and antioxidants activity

in seedlings of broad bean (Vicia faba L.). J. Environ. Biol. 32: 707–711.