Microbial-mediated management of organic xenobiotic pollutants in agricultural lands

Abstract

Contamination of agricultural soil by organic xenobiotic compounds is becoming a serious problem in most of the developed and developing countries. Chemicals foreign to an organism or chemicals not natural to an ecosystem are considered as xenobiotic for an organism, and upon exposure they impose toxicity threats to the organism. The term is mainly used in the context of pollutants such as chemical fertilizers, pesticides, dyes, dioxins, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) and their side effect on the biota. High concentrations of these xenobiotics create a biological imbalance in soil leading to surface and groundwater pollution. Inside plants they block the functional groups of biologically important molecules like enzymes, transport system of nutrient ions, polynucleotides, etc. The degradation of these organic xenobiotic pollutants in nature is a serious challenge and microorganisms have been observed to play a vital role in their degradation. They transform hazardous organic xenobiotic compound into harmless or less hazardous form, generally carbon dioxide, water, methane, and nitrogen. The different groups of microbes produce different types of enzymes and organic acids that act on recalcitrant compounds and degrade them to simpler forms. As a consequence of biodegradation of xenobiotic compounds, microorganisms are helpful to overcome environmental pollution and considered as eco-friendly. This chapter tries to elaborate some of the mechanisms employed by the microorganisms to carry out the xenobiotic degradation and remediation process along with different genera of microbes involved in the process.