Assessment of Chlorpyrifos degradation using Eudrilus eugeniae and microbial consortium
Overuse of pesticides causes serious threats to the environment and public health. The ecological risk associated with contaminated soils depends on many physicochemical and biological processes that govern the transport and transformation of pesticides. Nevertheless, the persistence of pesticides in soil is a serious threat to both below and above ground organisms which play key roles in sustaining soil functions. One of the viable methods to decontaminate soil is by utilizing living soil biota selectively. This process called bioremediation. Bioremediation has traditionally been employed to remove chemical residues from soil or to lessen their toxicity levels. Although microbes have been extensively used for bioremediation, chemical breakdown, and remediation are significantly aided by certain dominant soil fauna, such as earthworms. Since they modify soil quality, earthworms are regarded as soil engineers. Earthworms can participate in the degradation of pesticide residues, either directly through the release of detoxifying enzymes in their gut or indirectly through their positive influence on microbial populations which could degrade pesticides. The earthworm supported pesticide degradation is largely confined to the gut microenvironment and the soil processed by the worms. With an increasing problem associated with persistent pesticides, its degradation was investigated using earthworms and earthworm-gut-derived microbes consortium. Chlorpyrifos-contaminated soil was collected and an experimental was set up for its degradation for 35 days. The physiochemical properties of soil as well as the health of the earthworm were studied throughout the incubation period. After 35 days the degradation kinetics was analyzed using HPLC. The degradation was positive in earthworms and earthworms gut-associated microbial consortium. However, using microorganisms for bioremediation requires understanding all physiological, microbiological, ecological, biochemical, and molecular aspects involved in pollutant transformation. By profiling microbial metabolic potential, which includes genes potentially involved in degradation in pesticide-exposed soils, the value of using a system-wide approach demonstrated that metagenomic profiles can potentially predict the breakdown of chemical compounds.