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Bioremediation for Sustainable Environmental Cleanup

waste handling. In such desperate situations, a few environmentally beneficial techniques can

overcome the restrictions associated with safe and cost-effective waste management technology.

Bioremediation approaches are increasingly being used as preferred methods for the detoxification

and biodegradation of pollutants in waste management and cleanup programs to revert contaminated

sites to their natural state, as they are cost-effective, natural environment friendly and long-term

solutions (Kumar et al. 2018).

Bioremediation is described as a process that uses living organisms, primarily microorganisms,

green plants and their enzymes, to remove, degrade, mineralize, transform and detoxify environmental

pollutants and hazardous components of waste into harmless or less toxic forms during the treatment

of contaminated sites in order to restore them to their original state (Azubuike et al. 2016). Pesticides,

polyaromatic hydrocarbons, halogenated petroleum hydrocarbons, nitroaromatic chemicals, metals

and industrial solvents have all been reduced in concentration and toxicity using the bioremediation

technique (Dua et al. 2002).

Microorganisms are used in bioremediation to immobilize or change the chemical structure of

pollutants found in soils, sediments, water and air, resulting in partial degradation, mineralization or

transformation of the molecule. However, most of the pollutants exhibit resistance to degradation,

which causes them to persist in the environment. Such accumulation may sometimes pose a serious

risk. Bioremediation techniques may be effectively set in polluted fields with the right use of

natural and engineered microorganisms. The treatment of polluted groundwater, soil, wetlands,

industrial wastes and sludge can all benefit from bioremediation approaches. Phytoremediation is

the process in which different types of plants are used in the bioremediation of contaminants. It

is a non-conventional, cost-effective and eco-friendly technology that utilizes plants to remove,

transform or stabilize a variety of contaminants located in water, sediments or soils (Prasad et al.

2001, Ladislas et al. 2012). This chapter aims to provide a brief overview of bioremediation and its

guiding principles, as well as the numerous bioremediation approaches, specifically the in-situ and

ex-situ remediation strategies, their benefits and drawbacks.

1.2 Bioremediation

Bioremediation is the “use of living organisms to clean up toxins from soil, water, or wastewater”

(EPA 2016). The utilization of living organisms to ameliorate the contaminated environment viz.

water, soil, etc., is referred to as bioremediation (Brar et al. 2006, Antizar-Ladislao 2010, Latha

and Reddy 2013). In other words, it is a technique for eliminating environmental contaminants

and restoring the natural ecosystem while also avoiding additional pollution. Various species

and their products, such as bacteria (bacterial bioremediation), fungi (mycoremediation), plants

(phytoremediation) and biomolecules generated from organisms, are engaged in bioremediation

processes (derivative bioremediation). Bioremediation can be aerobic (Wiegel and Wu 2000,

Bedard and May 1995) or anaerobic (Komancová et al. 2003). Bioremediation can occur naturally,

which is referred to as “natural attenuation” or it can take place artificially, which is referred to

as “biostimulation”. Note that not all toxins can be effectively removed with bioremediation.

Bioremediation aids humanity and society in dealing with harmful chemical pollutants that, if not

removed or rendered safe, may be damaging to human health and the environment.

1.3 Principles of Bioremediation

Recent research in ecology has revealed a variety of possibilities for improving biological systems.

The remediation of contaminated water and land regions is one of these studies’ notable successes.

Living organisms including bacteria, fungi and algae, as well as plants, are utilized in bioremediation

to break down and detoxify dangerous contaminants in the environment, converting them to CO2,

H2O, microbial biomass and metabolites. These microorganisms might be native to the polluted

location or they could have been isolated elsewhere and transported to the contaminated site.

Different types of organisms are involved in the biodegradation of a substance. A process known