251. Current Methods of Enhancing Bacterial Bioremediation of Pesticide Residues in Agricultural Farmlands
- Author
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Justus M. Onguso and Saphan Ochieng Anode
- Subjects
education.field_of_study ,Operon ,Population ,Biology ,chemistry.chemical_compound ,Metabolic pathway ,Bioremediation ,Plasmid ,chemistry ,Biochemistry ,Metagenomics ,Horizontal gene transfer ,Xenobiotic ,education - Abstract
The accumulation of recalcitrant xenobiotic compounds is due to continuous efflux from population and agricultural and industrial inputs that have created a serious impact on the pristine nature of our aquatic and terrestrial environment. Apart from this, these compounds are mostly carcinogenic, posing health hazards which persist over a long period of time. Metabolic pathways and specific operon systems have been found in diverse but limited groups of microbes that are responsible for the transformation of xenobiotic compounds. Distinct catabolic genes are either present on mobile genetic elements, such as transposons and plasmids, or the chromosome itself that facilitates horizontal gene transfer and enhances the rapid microbial transformation of toxic xenobiotic chemical compounds. Both natural and anthropogenic activities result in the accumulation of wide ranges of toxic xenobiotic compounds in the environment, causing a global concern. Bacteria, fungi, and actinomycetes are the main transformers and pesticide degraders. They generally biotransform pesticides and other xenobiotics by introducing minor chemical structural changes to the molecule, rendering them nontoxic. Several bacterial genera are adapted to grow in pesticide contaminated soils. These microorganisms have enzymes involved in the hydrolysis of P-O, P-F, P-S, C-Cl, P-C, and other chemical bonds, which are found in a wide variety of chemical pesticides. Most of the genes responsible for catabolic degradation are located on the chromosomes, but in a few cases, these genes are found in plasmids or transposons. The recent advances in metagenomics and whole genome sequencing have opened up new avenues for searching the novel pollutant degradative genes and their regulatory elements from both culturable and nonculturable microorganisms from the environment. Microorganisms respond differently to various kinds of stresses and gain fitness in the polluted environment. This process can be accelerated by applying genetic engineering techniques. The recombinant DNA and other molecular biological techniques have enabled amplification; disruption, and/or modification of the targeted genes that encode the enzymes in the metabolic pathways; minimization of pathway bottlenecks; enhancement of redox and energy generation; and recruiting heterologous genes to give new characteristics.
- Published
- 2021
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