Aerobic bacterial transformation and biodegradation of dioxins: a review

Abstract

Waste generation tends to surge in quantum as the population and living conditions grow. A group of structurally related chemicals of dibenzofurans and dibenzo-p-dioxins including their chlorinated congeners collectively known as dioxins are among the most lethal environmental pollutants formed during different anthropogenic activities. Removal of dioxins from the environment is challenging due to their persistence, recalcitrance to biodegradation, and prevalent nature. Dioxin elimination through the biological approach is considered both economically and environmentally as a better substitute to physicochemical conventional approaches. Bacterial aerobic degradation of these compounds is through two major catabolic routes: lateral and angular dioxygenation pathways. Information on the diversity of bacteria with aerobic dioxin degradation capability has accumulated over the years and efforts have been made to harness this fundamental knowledge to cleanup dioxin-polluted soils. This paper covers the previous decades and recent developments on bacterial diversity and aerobic bacterial transformation, degradation, and bioremediation of dioxins in contaminated systems.

Remarkable Shift In Structural And Functional Properties of An Animal Charcoal Polluted Soil Accentuated By Inorganic Nutrients Amendment

“…Dioxins, a group of structurally related chemicals, consist of dibenzo-p-dioxins, its 75 analogue of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans, its 135 congeners of polychlorinated dibenzofurans (PCDFs) dictated by the numbering and positions of the chlorine atoms in the dioxin/furan molecule (Kulkarni et al 2008). They are a common by-product of incomplete combustion and are known not only to be highly refractive, but also some of the most toxic and carcinogenic group of pollutants (Saibu et al 2020a). Some bacterial strains with dioxin and its analogue dibenzofuran degradation potentials were recently reported from polluted systems in Nigeria (Saibu et al 2020b).…”

A review of persistent organic pollutants: dioxins, furans, and their associated nitrogenated analogues

“…Evidently, dioxins are not easily metabolized and consequently this makes their elimination or degradation extremely slow [97]. Nonetheless, dioxins are eliminated through faeces and negligibly via the kidneys in form of urine [104].…”

“…This clean-up of the environment by bacterial degradation of PCDD/Fs involves both aerobic and anaerobic processes [12,99]. It is important to note that the reaction products of these catabolic reactions can be mineralized further and directed into the biogeochemical cycle because incomplete degradation can result into the formation and accumulation of more toxic metabolites that can be more toxic than their primary substrates [97].…”

“…Other environmental pollutants which are viewed as by-products of combustion and industrial activities, and are categorized as neither dioxins, dioxin-like nor furans include aliphatic and aromatic hydrocarbons, chlorine containing aromatics, some pesticides and herbicides applied in agricultural practices [97], nonetheless, dioxins and furan including their associated nitrogenated analogues remain a novel group of notorious environmental toxins. Remarkably, dioxins and dioxin-like compounds may be polychlorinated aromatic chemicals which are well established carcinogens and mutagens widely reported to cause adverse damage to biological tissues which ultimately result in oxidative stress, cancer, and cardio pulmonary diseases of grave concern [62].…”

“…Remarkably, dioxins and dioxin-like compounds may be polychlorinated aromatic chemicals which are well established carcinogens and mutagens widely reported to cause adverse damage to biological tissues which ultimately result in oxidative stress, cancer, and cardio pulmonary diseases of grave concern [62]. Synthesis of haloaromatic chemicals and incineration of chlorine containing organic materials are other important sources of dioxins [97]. Moreover, thermochemical processes yield PAHs [127] and oxy-PAHs [36] which are well known precursors for the synthesis of dioxins, dibenzofurans, and their attendant analogues of the nitrogenated type [135].…”