Institut für Siedlungswasserbau, Wassergüte-und Abfallwirtschaft, Department of Biological Waste Air Cleaning, Universität Stuttgart, Stuttgart, Germany.
Appl Microbiol Biotechnol. 2013 Jun;97(12):5605-14. doi: 10.1007/s00253-012-4388-2. Epub 2012 Sep 15.
A halobenzene-degrading bacterium, Burkholderia fungorum FLU100 (DSM 23736), was isolated due to its outstanding trait to degrade fluorobenzene. Besides fluorobenzene, it utilizes, even in random mixtures, chlorobenzene, bromobenzene, iodobenzene, benzene, and toluene as sole sources of carbon and energy. FLU100 mineralizes mono-halogenated benzenes almost stoichiometrically (according to halide balance); after a lag phase, it also degrades 3-fluorophenol and 3-chlorophenol completely. The FLU100-derived transposon Tn5-mutant FLU100-P14R22 revealed 3-halocatechol to be a central metabolite of this new halobenzene degradation pathway. In FLU100, halocatechols are-as expected-strictly subject to ortho-cleavage of the catechol ring, with meta-cleavage never been observed. The strain is able to completely mineralize 3-fluorocatechol, the principal catecholic metabolite being nearly exclusively formed from fluorobenzene. The temporarily excreted 2-fluoromuconate formed thereof in turn is subsequently metabolized completely. This important finding falsifies the customary opinion of the persistence of 2-fluoromuconate valid up to now. The degradation of 4-fluorocatechol, however, being a very minor intermediate in FLU100, is substantially slower and incomplete and leads to the accumulation of uncharacterized derivatives of muconic acid and muconolactone in the medium. This branch therefore does not seem to be productive. To our knowledge, this represents the first example of the complete metabolism of 3-fluorocatechol via 2-fluoromuconate, a metabolite hitherto described as a dead-end metabolite in fluoroaromatic degradation.
一株能降解氟苯的不动杆菌，弗氏伯克霍尔德菌 FLU100（DSM 23736），因其能降解氟苯这一突出特性而被分离得到。除了氟苯，它还可以利用氯苯、溴苯、碘苯、苯和甲苯作为唯一的碳源和能源，甚至在随机混合物中也可以利用这些物质。FLU100 几乎按卤化物平衡的化学计量数矿化单卤代苯；在滞后阶段后，它还能完全降解 3-氟苯酚和 3-氯苯酚。FLU100 衍生的转座子 Tn5 突变体 FLU100-P14R22 表明 3-卤代邻苯二酚是该新的卤代苯降解途径的中心代谢物。在 FLU100 中，邻苯二酚严格按照儿茶酚环的邻位裂解，从未观察到间位裂解。该菌株能够完全矿化 3-氟邻苯二酚，主要的儿茶酚代谢物几乎完全由氟苯形成。由此暂时排泄的 2-氟乌头酸继而被完全代谢。这一重要发现推翻了迄今普遍认为 2-氟乌头酸一直存在的观点。然而，4-氟邻苯二酚在 FLU100 中只是一个非常次要的中间产物，其降解速度非常慢且不完全，导致培养基中积累了未鉴定的粘康酸和粘康酸内酯衍生物。因此，这个分支似乎没有生产力。据我们所知，这代表了通过 2-氟乌头酸完全代谢 3-氟邻苯二酚的首例，而 2-氟乌头酸是迄今在氟代芳烃降解中被描述为死端代谢物的代谢物。
