Bioremediation of Pesticides: An Eco-Friendly Approach for Environment Sustainability

Abstract

Various pesticides including organochlorines, organophosphates, carbamate, pyrethroids, chloronicotinyl etc., are used in agriculture for protection against plant diseases and insects. Only a fraction of the applied pesticides is utilized in killing of target pests and the leftover residual pesticides either remains associated with cereal grains, vegetables, and fruits or may cause environmental pollution. In addition to the traditional physical and chemical degradation methods, the microbial degradation method is commonly more efficient and low-cost method used for pesticide degradation. Microorganisms have been characterized which have the capability to degrade residual pesticides. The microbes that demolish these pesticides use the pesticides as nutrients and break them down into tiny nontoxic molecules. Pesticide degrading microbes belong to different microbial groups, i.e., bacteria, fungi, actinomycetes, and algae. Bacteria possessing pesticide degradation capability include Pseudomonas spp., Bacillus spp., Burkholderia, Klebsiella spp., Streptomyces, etc. and the fungi include Trichoderma spp., Aspergillus spp., Phanerochaete chrysosporium, white rot fungi, etc., whereas algae include Chlamydomonas and marine Chlorella. Major reactions in pesticide destruction include mineralization and co-metabolism. Pesticide degradation is influenced by many factors such as type of pesticide, type of microorganism, temperature, humidity, and acidity in the environment. Plasmid-located genes usually encode many enzymes and degrade a large number of pesticides. Microorganisms may acquire pesticide-degradation capabilities in soil through horizontal gene transfer from degradative plasmids, by modification of substrate specificity, or through altered regulation of preexisting enzymes. With the progress of molecular biology, the genetically engineered rhizobacteria may be built to enhance the bioremediation of pollutants and pesticides. Such recombinant microbial populations may be of immense value in bioremediation of diverse pesticides from the surroundings.