Naturally Occurring Organohalogen Compounds - A Comprehensive Update

Technical Note: Reactivity of C1 and C2 organohalogens formation – from plant litter to bacteria

“…Natural halogenation processes, promoted either by thermal (Hamilton et al, 2003;Weissflog et al, 2005), enzymatic (Hoekstra et al, 1998;Blasiak and Drennan, 2009), or Fenton/Fenton-like reactions (Fahimi et al, 2003;Huber et al, 2009), contribute significantly to the global budget of these hazardous organohalogens (Gribble, 2010). For example, the chloroform flux through the environment is estimated at 660 ± 220 × 10 9 g yr −1 with 90 % of natural origin (McCulloch, 2003), and that of bromoform at ∼ 220 × 10 9 g yr −1 with 70 % from macroalgae (Carpenter and Liss, 2000).…”

“…For example, the chloroform flux through the environment is estimated at 660 ± 220 × 10 9 g yr −1 with 90 % of natural origin (McCulloch, 2003), and that of bromoform at ∼ 220 × 10 9 g yr −1 with 70 % from macroalgae (Carpenter and Liss, 2000). Abiotically, aliphatic volatile organohalogens were released from senescent and dead leaves (Hamilton et al, 2003), Fe-oxyhydroxide and halide containing soil or sediment (or with H 2 O 2 ; Fahimi et al, 2003;Huber et al, 2009), and emissions from savannah fires, volcanoes, hydrothermal sources, and salt mines (Weissflog et al, 2005;Gribble, 2010). Biotically, enzymes like haloperoxidases and halogenases widespread in soils and oceans are thought to contribute the major sources of environmental organohalogens (Nightingale et al, 1995;Hoekstra et al, 1998;Öberg, 2002;Reddy et al, 2002;Ortiz-Bermudez et al, 2007;Blasiak and Drennan, 2009;Wagner et al, 2009).…”

Chlorinated organic compounds produced byFusarium graminearum

“…Mycelia of five day old cultures were scrapped from the agar plates and ground with liquid nitrogen using a mortar and pestle. Into four 2 ml epperndoff tubes containing the ground mycelia weighing 0.10 grams, extraction reagents, 750 µL methanol-D 4 , and 750 µL deuterium oxide were added. Both extraction reagents were supplied by Sigma-Aldrich® Corporation.…”

“…From the compounds represented by the spectra, known chlorinated compounds were selected and presented in Table 1 below. More than 220 organochlorines are produced naturally by the environment [4,5]. It has previously been found that fungal parasites of plants produce organically bound chlorine during substrate degradation.…”

PCB dechlorinases revealed at last

“…It may just be that the RDases in D. mccartyi have flexible regions that permit rapid adaptation when potential new substrates become available. Or it could be that the PCB RDases actually evolved to dehalogenate some of the thousands of naturally chlorinated aromatic compounds that exist (16) and just happen to work on PCBs.…”