Chapter 2 - Efficacy of microbes in removal of pesticides from watershed system

Abstract

Excessive use of pesticides for increasing crop production has resulted in creating environmental imbalances due to its potential for biomagnifications. The rigorous application of chemical pesticides tends to prove hazardous to the innocuous organisms and surrounding environment of the applied site. The pesticides get disposed of in the adjoining downstream environments through the agricultural runoff followed by groundwater contamination, thereby reaching the watershed systems. Thus, there is an urgent need for sustainable management of these pollutants by adopting eco-friendly approaches. The microbial and enzymatic degradation of pesticides are encouraged by researchers due to emanation of environmental sustainability, cost-effectiveness, and time efficiency. Several bacteria, fungi, and algae have potential to metabolize pesticides by altering their chemical structures causing amputation or degradation of pesticides and, therefore, facilitating their removal from the polluted environment. Similarly, enzymes such as laccases and peroxidases can efficiently cleave bonds in pesticide molecules converting it to lesser toxic metabolites. The use of potential strains of microbes in axenic cultures is being explored for compelling bioremediation of pesticides. Using microbial cultures for remediation has limited applicability due to lack of proper knowledge about their interactions with other indigenous microbes at the applied site. The microbial adaptation under environmental variations is unpredictable; therefore, giving inconsistent performance for pesticide remediation will further challenge to limit the practical applications of microbial cultures. The study reviews the recent literature on the prospect and challenges of ecofriendly bioremediation approaches for the reclamation of pesticides in downstream watershed systems. The underlying mechanism of the microbe- and enzyme-mediated bioremediation of pesticides with sustainable research prospective has also been discussed.