Microbe-Assisted Bioremediation of Pesticides from Contaminated Habitats 115

Figure 7.2. Mechanisms of pesticide degradation in bacterial system.

metabolite is conjugated to a sugar or amino acid, that increases its water solubility and reduces its

toxicity. During the third phase, phase two metabolites are converted into secondary conjugates,

which are also non-toxic (Ramakrishnan et al. 2011). The overall metabolism of pesticides by

enzymes proves to be favorable, as enzymes are more resistant to environmental conditions, which

makes it easier for them to remove pesticides more efficiently from affected areas (Huang et al.

2008). Therefore, it is imperative to identify species of bacteria that can thrive in extreme conditions

and completely degrade pesticides. A combination of mechanistic approaches and microbial genetic

advancement can enhance sustainable pesticide bioremediation by identifying the most effective

bacterial strains or bacterial consortia.

7.4.2 Phyco-assisted Degradation

The persistence of pesticides creates a grave threat to the environment, and their removal is crucial

in maintaining stability in the ecosystem (Bodin 2014). For many years, biological approaches have

been used in the removal of inorganic pollutants such as pesticides. There is a growing interest in

cyanobacteria and micro- and macroalgae as potent organisms for removing pesticides. It has been

shown that these organisms easily adapt to environmental changes and can grow efficiently under

various stress conditions (Mata et al. 2010). A wide range of photosynthetic algae exist, ranging

from single cells to multicellular organisms (Singh et al. 2020). They can grow in the presence and

absence of light and utilize organic carbon as an energy source (Subashchandrabose et al. 2013). As

part of a sustainable future, these photosynthetic microorganisms can be used for the remediation

of pesticides at contaminated sites. Research on phycoremediation technology, i.e., the utilization

of microalgae/cyanobacteria and their consortia as bioremediating agents, has proved to have

promising potential. Several authors have reported that common algal strains can remove pesticides

from contaminated environments, mainly by biosorption, bioaccumulation and biodegradation

(Table 7.3) (Verasoundarapandian et al. 2022).

Pesticide biosorption occurs in both living and dead photosynthetic organisms, as this

mechanism is not dependent on energy for the removal of pesticides in contaminated environments.