Recent Developments in Microbial Biotransformation and Biodegradation of Dioxins

Abstract

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), commonly known as dioxins (PCDD/Fs), are toxic environmental pollutants formed from various sources. Elimination of these pollutants from the environment is a difficult task due to their persistent and ubiquitous nature. Removal of dioxins by biological degradation (biodegradation) is considered a feasible method as an alternative to other expensive physicochemical approaches. Biodegradation of dioxins has been extensively studied in several microorganisms, and details concerning biodiversity, biodegradation, biochemistry and molecular biology of this process have accumulated during the last three decades. There are several microbial mechanisms responsible for biodegradation of dioxins, including oxidative degradation by dioxygenase-containing aerobic bacteria, bacterial and fungal cytochrome P-450, fungal lignolytic enzymes, reductive dechlorination by anaerobic bacteria, and direct ether ring cleavage by fungi containing etherase-like enzymes. Many attempts have been made to bioremediate PCDD/Fs using this basic knowledge of microbial dioxin degradation. This review emphasizes the present knowledge and recent advancements in the microbial biotransformation, biodegradation and bioremediation of dioxins.

Pollutants Biodegradation by Fungi

“…Removal of dioxins by biological degradation is considered a feasible method as an alternative to other expensive physic-chemistry approaches [80]. Different dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were studied for degradation by fungi such as Phlebia radiata I-5-6 [81,82,83], P. acerina, P. lindtneri and P. brevispora which can hydroxylate and methoxylate PCDDs [84], and Phanerochaete chrysosporium DSM 6909, P. chrysosporium DSM 1556, Irpex sp.…”

Isolation and characterization of Pseudomonas sp. strain capable of degrading diethylstilbestrol

“…Although these methods could effectively remove DES from the environments, the whole processes needed specific cells in site, such as cells with ultrasound sample, PbO 2 anode, and stainless steel cathode, or certain equipment including highpressure mercury lamp and ozone generator. Nowadays, transformation of various organic pollutants by microorganisms has been demonstrated to be a more effective and facile, and less expensive way to eliminate pollution in the environments compared to the physicochemical methods (Chang 2008;Singh et al 2008). Lee and Liu (2002) had reported the degradation of other EDCs, 17β-estradiol and its metabolites, by sewage bacteria.…”

Mentha spicata and Salvia fruticosa composts as soil amendments in tomato cultivation

“…This is because the microbial communities are involved in the nutrient cycling and perform many other essential roles, such as suppression of plant pathogens via competition for nutrients and/or production of siderophores or antibiotics (Berg 2009;Loper and Buyer 1991), stabilisation of soil aggregates (Forster 1990), degradation of xenobiotics and environmental pollutants (Chang 2008;Peng et al 2008), modification of the activity of allelochemicals (Inderjit 2005) and production of plant growth regulators (Arkhipova et al 2007;Baca and Elmerich 2007;Bottini et al 2004;Tsavkelova et al 2005). The experiments conducted in this study did not allow us to determine the exact role of the dramatically increased communities of bacteria and fungi in the soils treated with composts of either aromatic plant.…”